docs: resubmit pr 17115 doc changes

credits: https://github.com/snitin315

Refs:
* eslint#17225
* eslint#17107

docs/src/extend/code-path-analysis.md

@@ -259,8 +259,7 @@ Please use a map of information instead.
 ```js
 function hasCb(node, context) {
     if (node.type.indexOf("Function") !== -1) {
-        const sourceCode = context.getSourceCode();
-
+        const sourceCode = context.sourceCode;
         return sourceCode.getDeclaredVariables(node).some(function(v) {
             return v.type === "Parameter" && v.name === "cb";
         });

docs/src/extend/custom-rules.md

@@ -147,7 +147,7 @@ Additionally, the `context` object has the following methods:
 * `getFilename()`: Returns the filename associated with the source.
 * `getPhysicalFilename()`: When linting a file, it returns the full path of the file on disk without any code block information. When linting text, it returns the value passed to `—stdin-filename` or `<text>` if not specified.
 * `getScope()`: (**Deprecated:** Use `SourceCode#getScope(node)` instead.) Returns the [scope](./scope-manager-interface#scope-interface) of the currently-traversed node. This information can be used to track references to variables.
-* `getSourceCode()`: Returns a `SourceCode` object that you can use to work with the source that was passed to ESLint (see [Accessing the Source Code](#accessing-the-source-code)).
+* `getSourceCode()`: (**Deprecated:** Use `context.sourceCode` instead.) Returns a `SourceCode` object that you can use to work with the source that was passed to ESLint (see [Accessing the Source Code](#accessing-the-source-code)).
 * `markVariableAsUsed(name)`: (**Deprecated:** Use `SourceCode#markVariableAsUsed(name, node)` instead.)  Marks a variable with the given name in the current scope as used. This affects the [no-unused-vars](../rules/no-unused-vars) rule. Returns `true` if a variable with the given name was found and marked as used, otherwise `false`.
 * `report(descriptor)`. Reports a problem in the code (see the [dedicated section](#reporting-problems)).
 
@@ -506,18 +506,20 @@ When using options, make sure that your rule has some logical defaults in case t
 
 ### Accessing the Source Code
 
-The `SourceCode` object is the main object for getting more information about the source code being linted. You can retrieve the `SourceCode` object at any time by using the `context.getSourceCode()` method:
+The `SourceCode` object is the main object for getting more information about the source code being linted. You can retrieve the `SourceCode` object at any time by using the `context.sourceCode` property:
 
 ```js
 module.exports = {
     create: function(context) {
-        var sourceCode = context.getSourceCode();
+        var sourceCode = context.sourceCode;
 
         // ...
     }
 };
 ```
 
+**Deprecated:** The `context.getSourceCode()` method is deprecated; make sure to use `context.sourceCode` property instead.
+
 Once you have an instance of `SourceCode`, you can use the following methods on it to work with the code:
 
 * `getText(node)`: Returns the source code for the given node. Omit `node` to get the whole source (see the [dedicated section](#accessing-the-source-text)).
@@ -706,7 +708,7 @@ To help with this, you can use the `sourceCode.markVariableAsUsed()` method. Thi
 ```js
 module.exports = {
     create: function(context) {
-        var sourceCode = context.getSourceCode();
+        var sourceCode = context.sourceCode;
 
         return {
             ReturnStatement(node) {