🧪 Integrate pymarkdown into pre-commit config

This is meant to ensure consistency in our Markdown content source.

Ref: https://pymarkdown.rtfd.io

Author: webknjaz

.github/ISSUE_TEMPLATE/bug-report.md

@@ -1,6 +1,8 @@
 ---
+
 name: Bug report
 about: Create a report to help us improve
+
 ---
 
 <!-- Describe the issue briefly here. -->

.github/ISSUE_TEMPLATE/feature-request.md

@@ -1,21 +1,32 @@
 ---
+
 name: Feature request
 about: Suggest an idea for this project
+
 ---
 
 #### What's the problem this feature will solve?
 
-<!-- What are you trying to do, that you are unable to achieve with pip-tools as it currently stands? -->
+<!--
+What are you trying to do, that you are unable to achieve with pip-tools as it
+currently stands?
+-->
 
 #### Describe the solution you'd like
 
 <!-- A clear and concise description of what you want to happen. -->
 
-<!-- Provide examples of real-world use cases that this would enable and how it solves the problem described above. -->
+<!--
+Provide examples of real-world use cases that this would enable and how it
+solves the problem described above.
+-->
 
 #### Alternative Solutions
 
-<!-- Have you tried to workaround the problem using pip-tools or other tools? Or a different approach to solving this issue? Please elaborate here. -->
+<!--
+Have you tried to workaround the problem using pip-tools or other tools? Or a
+different approach to solving this issue? Please elaborate here.
+-->
 
 #### Additional context
 

.github/PULL_REQUEST_TEMPLATE.md

@@ -3,9 +3,14 @@
 ##### Contributor checklist
 
 - [ ] Included tests for the changes.
-- [ ] A change note is created in `changelog.d/` (see [`changelog.d/README.md`](https://github.com/jazzband/pip-tools/blob/main/changelog.d/#readme) for instructions) or the PR text says "no changelog needed".
+- [ ] A change note is created in `changelog.d/` (see [`changelog.d/README.md`]
+      for instructions) or the PR text says "no changelog needed".
+
+[`changelog.d/README.md`]:
+https://github.com/jazzband/pip-tools/blob/main/changelog.d/#readme
 
 ##### Maintainer checklist
 
 - [ ] If no changelog is needed, apply the `bot:chronographer:skip` label.
-- [ ] Assign the PR to an existing or new milestone for the target version (following [Semantic Versioning](https://blog.versioneye.com/2014/01/16/semantic-versioning/)).
+- [ ] Assign the PR to an existing or new milestone for the target version
+      (following Semantic Versioning).

.pre-commit-config.yaml

@@ -107,4 +107,9 @@ repos:
     hooks:
       - id: actionlint
 
+  - repo: https://github.com/jackdewinter/pymarkdown.git
+    rev: v0.9.33
+    hooks:
+      - id: pymarkdown
+
 ...