docs: Add pre-commit documentation

docs/docs/development/pre-commit.md

@@ -0,0 +1,37 @@
+---
+title: Pre-commit
+---
+
+ZMK uses [pre-commit](https://pre-commit.com/) to check for common errors and make sure the codebase is formatted consistently.
+
+Pre-commit is run on every pull request. You can also install it locally to get the same checks run on every commit you make _before_ you submit a pull request.
+
+## Installing pre-commit
+
+Open a terminal and run:
+
+```bash
+pip3 install pre-commit
+```
+
+If this doesn't work, make sure [Python](https://www.python.org/) is installed and try again.
+
+## Enabling Commit Hooks
+
+Now that pre-commit is installed on your PC, you need to install it into the ZMK repo to enable it. Open a terminal to the ZMK repo directory and run:
+
+```bash
+pre-commit install
+```
+
+This should print a message such as
+
+```
+pre-commit installed at .git\hooks\pre-commit
+```
+
+Pre-commit will now automatically check your changes whenever you run `git commit`. If it detects a problem, it will describe the problem and cancel the commit. For simple problems such as incorrect formatting, it will also automatically fix the files so you can just `git add` them and try again.
+
+## Automatically Enabling pre-commit
+
+Pre-commit can be configured to automatically install itself into any newly cloned repository, so you don't have to remember to run `pre-commit install`. See the [pre-commit documentation](https://pre-commit.com/#automatically-enabling-pre-commit-on-repositories) for instructions.

docs/sidebars.js

@@ -71,6 +71,7 @@ module.exports = {
     ],
     Development: [
       "development/clean-room",
+      "development/pre-commit",
       "development/documentation",
       "development/setup",
       "development/build-flash",