refactor: Add more checks to pre-commit

Updated existing pre-commit hooks and added some new hooks:

- Remove trailing whitespace
- Ensure every non-empty file ends with a new line
- Check YAML file validity
- Prevent adding large files
- Ensure any scripts with shebangs are executable

Added a GitHub action to run pre-commit on every commit. Removed any
existing actions which duplicate pre-commit.

Ran pre-commit on the codebase.

docs/src/templates/setup.sh.mustache

@@ -97,7 +97,7 @@ select opt in "${options[@]}" "Quit"; do
             keyboard_arch=${keyboards_arch[$keyboard_index]}
             keyboard_basedir=${keyboards_basedir[$keyboard_index]}
             keyboard_title=${options[$keyboard_index]}
-            keyboard_sibling_var=${keyboard}_siblings[@]                                                  
+            keyboard_sibling_var=${keyboard}_siblings[@]
             keyboard_sibling_first=${keyboard}_siblings[0]
             if [ -n "${!keyboard_sibling_first}" ]; then
                 keyboard_siblings=${!keyboard_sibling_var}