chore: update issue templates

Author: alecthomas

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,31 @@
+name: 🐞 Bug
+description: File a bug/issue
+title: "<title>"
+labels: ["bug"]
+body:
+  - type: checkboxes
+    attributes:
+      label: Is there an existing issue for this?
+      description: Please search to see if an issue already exists for the bug you encountered.
+      options:
+        - label: I have searched the existing issues
+          required: true
+  - type: textarea
+    attributes:
+      label: Describe the bug
+      description: |
+        A clear and concise description of what the bug is. Screenshots are often helpful here.
+
+        Do *NOT* just paste a link to other issues on GitHub.
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: To Reproduce
+      description: |
+        1. Reproduce your issue in the [Chroma Playground](https://swapoff.org/chroma/playground/), then click the _copy_ icon to copy a shareable link for your issue. Consider using `[markdown links](URL)` to minimise the visual noise of the links.
+        2. Provide input text and a command-line invocation of `chroma` that reproduces your problem. eg. For Hugo this might be something like `chroma -s monokailight --html --html-lines --html-lines-table --html-inline-styles <source>`
+
+        Do *NOT* provide configuration for another tool (eg. Hugo, Gitea). My time is limited and if you want me to fix your issue, help me help you.
+    validations:
+      required: true

.github/ISSUE_TEMPLATE/bug_report.yaml

@@ -0,0 +1,27 @@
+name: Feature request
+description: Suggest an idea for this project
+title: "<title>"
+labels: ["feature request"]
+body:
+  - type: checkboxes
+    attributes:
+      label: Is there an existing issue for this?
+      description: Please search to see if an issue already exists for the feature you're requesting.
+      options:
+        - label: I have searched the existing issues
+          required: true
+  - type: textarea
+    attributes:
+      label: What problem does this feature solve?
+      description: |
+        Please check the Chroma [README](https://github.com/alecthomas/chroma) and command-line tool to ensure this isn't an already solved problem.
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: What feature do you propose?
+      description: |
+        The feature should describe a change to Chroma's code, not lexers.
+        For lexers, fill out the "Lexer request" form.
+    validations:
+      required: true

.github/ISSUE_TEMPLATE/feature_request.md

@@ -0,0 +1,29 @@
+name: Lexer request
+description: Suggest the addition of a lexer
+title: "<title>"
+labels: ["help wanted", "lexer missing"]
+body:
+  - type: checkboxes
+    attributes:
+      label: Is there an existing issue for this?
+      description: Please search to see if an issue already exists for the lexer you're requesting.
+      options:
+        - label: I have searched the existing issues
+          required: true
+  - type: textarea
+    attributes:
+      label: What is the missing lexer?
+      description: |
+        Please note that lexers are contributed by the community. Your best option is to contribute this yourself.
+
+        Lexers are defined in XML (see the [existing lexers](https://github.com/alecthomas/chroma/tree/master/lexers/embedded) for examples).
+        You can test your lexer with the Chroma command-line, `chroma --lexer=my-lexer.xml example-file.lang`
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: Links to existing syntax definitions
+      description: |
+        Provide links to existing syntax definitions in Textmate, etc.
+    validations:
+      required: true