Clarify warning source about underspecified corejs option in preset-env.

packages/babel-preset-env/src/normalize-options.js

@@ -160,7 +160,8 @@ export function normalizeCoreJSOption(
   if (useBuiltIns && corejs === undefined) {
     rawVersion = 2;
     console.warn(
-      "\nWARNING: We noticed you're using the `useBuiltIns` option without declaring a " +
+      "\n[babel-preset-env]" +
+        "\nWARNING: We noticed you're using the `useBuiltIns` option without declaring a " +
         "core-js version. Currently, we assume version 2.x when no version " +
         "is passed. Since this default version will likely change in future " +
         "versions of Babel, we recommend explicitly setting the core-js version " +
@@ -170,7 +171,9 @@ export function normalizeCoreJSOption(
         "`dependencies` section. If it doesn't, you need to run one of the " +
         "following commands:\n\n" +
         "  npm install --save core-js@2    npm install --save core-js@3\n" +
-        "  yarn add core-js@2              yarn add core-js@3\n",
+        "  yarn add core-js@2              yarn add core-js@3\n\n" +
+        "More info about useBuiltIns: https://babeljs.io/docs/en/babel-preset-env#usebuiltins\n" +
+        "More info about core-js: https://babeljs.io/docs/en/babel-preset-env#corejs",
     );
   } else if (typeof corejs === "object" && corejs !== null) {
     rawVersion = corejs.version;
@@ -183,7 +186,8 @@ export function normalizeCoreJSOption(
 
   if (!useBuiltIns && version) {
     console.log(
-      "\nThe `corejs` option only has an effect when the `useBuiltIns` option is not `false`\n",
+      "\n[babel-preset-env]" +
+        "\nThe `corejs` option only has an effect when the `useBuiltIns` option is not `false`\n",
     );
   }
 

packages/babel-preset-env/test/fixtures/debug/corejs-without-usebuiltins/stdout.txt

@@ -1,3 +1,4 @@
+[babel-preset-env]
 The `corejs` option only has an effect when the `useBuiltIns` option is not `false`
 
 @babel/preset-env: `DEBUG` option

packages/babel-preset-env/test/fixtures/debug/entry-no-corejs-no-import/stderr.txt

@@ -1,6 +1,10 @@
+[babel-preset-env]
 WARNING: We noticed you're using the `useBuiltIns` option without declaring a core-js version. Currently, we assume version 2.x when no version is passed. Since this default version will likely change in future versions of Babel, we recommend explicitly setting the core-js version you are using via the `corejs` option.
 
 You should also be sure that the version you pass to the `corejs` option matches the version specified in your `package.json`'s `dependencies` section. If it doesn't, you need to run one of the following commands:
 
   npm install --save core-js@2    npm install --save core-js@3
-  yarn add core-js@2              yarn add core-js@3
+  yarn add core-js@2              yarn add core-js@3
+
+More info about useBuiltIns: https://babeljs.io/docs/en/babel-preset-env#usebuiltins
+More info about core-js: https://babeljs.io/docs/en/babel-preset-env#corejs

packages/babel-preset-env/test/fixtures/debug/entry-no-corejs-shippedProposals/stderr.txt

@@ -1,6 +1,10 @@
+[babel-preset-env]
 WARNING: We noticed you're using the `useBuiltIns` option without declaring a core-js version. Currently, we assume version 2.x when no version is passed. Since this default version will likely change in future versions of Babel, we recommend explicitly setting the core-js version you are using via the `corejs` option.
 
 You should also be sure that the version you pass to the `corejs` option matches the version specified in your `package.json`'s `dependencies` section. If it doesn't, you need to run one of the following commands:
 
   npm install --save core-js@2    npm install --save core-js@3
-  yarn add core-js@2              yarn add core-js@3
+  yarn add core-js@2              yarn add core-js@3
+
+More info about useBuiltIns: https://babeljs.io/docs/en/babel-preset-env#usebuiltins
+More info about core-js: https://babeljs.io/docs/en/babel-preset-env#corejs

packages/babel-preset-env/test/fixtures/debug/entry-no-corejs-uglify/stderr.txt

@@ -1,6 +1,10 @@
+[babel-preset-env]
 WARNING: We noticed you're using the `useBuiltIns` option without declaring a core-js version. Currently, we assume version 2.x when no version is passed. Since this default version will likely change in future versions of Babel, we recommend explicitly setting the core-js version you are using via the `corejs` option.
 
 You should also be sure that the version you pass to the `corejs` option matches the version specified in your `package.json`'s `dependencies` section. If it doesn't, you need to run one of the following commands:
 
   npm install --save core-js@2    npm install --save core-js@3
-  yarn add core-js@2              yarn add core-js@3
+  yarn add core-js@2              yarn add core-js@3
+
+More info about useBuiltIns: https://babeljs.io/docs/en/babel-preset-env#usebuiltins
+More info about core-js: https://babeljs.io/docs/en/babel-preset-env#corejs

packages/babel-preset-env/test/fixtures/debug/entry-no-corejs/stderr.txt

@@ -1,6 +1,10 @@
+[babel-preset-env]
 WARNING: We noticed you're using the `useBuiltIns` option without declaring a core-js version. Currently, we assume version 2.x when no version is passed. Since this default version will likely change in future versions of Babel, we recommend explicitly setting the core-js version you are using via the `corejs` option.
 
 You should also be sure that the version you pass to the `corejs` option matches the version specified in your `package.json`'s `dependencies` section. If it doesn't, you need to run one of the following commands:
 
   npm install --save core-js@2    npm install --save core-js@3
-  yarn add core-js@2              yarn add core-js@3
+  yarn add core-js@2              yarn add core-js@3
+
+More info about useBuiltIns: https://babeljs.io/docs/en/babel-preset-env#usebuiltins
+More info about core-js: https://babeljs.io/docs/en/babel-preset-env#corejs

packages/babel-preset-env/test/fixtures/debug/usage-no-corejs-1/stderr.txt

@@ -1,6 +1,10 @@
+[babel-preset-env]
 WARNING: We noticed you're using the `useBuiltIns` option without declaring a core-js version. Currently, we assume version 2.x when no version is passed. Since this default version will likely change in future versions of Babel, we recommend explicitly setting the core-js version you are using via the `corejs` option.
 
 You should also be sure that the version you pass to the `corejs` option matches the version specified in your `package.json`'s `dependencies` section. If it doesn't, you need to run one of the following commands:
 
   npm install --save core-js@2    npm install --save core-js@3
   yarn add core-js@2              yarn add core-js@3
+
+More info about useBuiltIns: https://babeljs.io/docs/en/babel-preset-env#usebuiltins
+More info about core-js: https://babeljs.io/docs/en/babel-preset-env#corejs

packages/babel-preset-env/test/fixtures/debug/usage-no-corejs-2/stderr.txt

@@ -1,6 +1,10 @@
+[babel-preset-env]
 WARNING: We noticed you're using the `useBuiltIns` option without declaring a core-js version. Currently, we assume version 2.x when no version is passed. Since this default version will likely change in future versions of Babel, we recommend explicitly setting the core-js version you are using via the `corejs` option.
 
 You should also be sure that the version you pass to the `corejs` option matches the version specified in your `package.json`'s `dependencies` section. If it doesn't, you need to run one of the following commands:
 
   npm install --save core-js@2    npm install --save core-js@3
   yarn add core-js@2              yarn add core-js@3
+
+More info about useBuiltIns: https://babeljs.io/docs/en/babel-preset-env#usebuiltins
+More info about core-js: https://babeljs.io/docs/en/babel-preset-env#corejs

packages/babel-preset-env/test/fixtures/debug/usage-no-corejs-none-1/stderr.txt

@@ -1,6 +1,10 @@
+[babel-preset-env]
 WARNING: We noticed you're using the `useBuiltIns` option without declaring a core-js version. Currently, we assume version 2.x when no version is passed. Since this default version will likely change in future versions of Babel, we recommend explicitly setting the core-js version you are using via the `corejs` option.
 
 You should also be sure that the version you pass to the `corejs` option matches the version specified in your `package.json`'s `dependencies` section. If it doesn't, you need to run one of the following commands:
 
   npm install --save core-js@2    npm install --save core-js@3
-  yarn add core-js@2              yarn add core-js@3
+  yarn add core-js@2              yarn add core-js@3
+
+More info about useBuiltIns: https://babeljs.io/docs/en/babel-preset-env#usebuiltins
+More info about core-js: https://babeljs.io/docs/en/babel-preset-env#corejs

packages/babel-preset-env/test/fixtures/debug/usage-no-corejs-none-2/stderr.txt

@@ -1,6 +1,10 @@
+[babel-preset-env]
 WARNING: We noticed you're using the `useBuiltIns` option without declaring a core-js version. Currently, we assume version 2.x when no version is passed. Since this default version will likely change in future versions of Babel, we recommend explicitly setting the core-js version you are using via the `corejs` option.
 
 You should also be sure that the version you pass to the `corejs` option matches the version specified in your `package.json`'s `dependencies` section. If it doesn't, you need to run one of the following commands:
 
   npm install --save core-js@2    npm install --save core-js@3
-  yarn add core-js@2              yarn add core-js@3
+  yarn add core-js@2              yarn add core-js@3
+
+More info about useBuiltIns: https://babeljs.io/docs/en/babel-preset-env#usebuiltins
+More info about core-js: https://babeljs.io/docs/en/babel-preset-env#corejs