Update the .gitignore file (#465)

The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).

- Added VS Code directory
- Improve structure
- Add comments to `.gitignore`

Reviewed-on: https://codeberg.org/Codeberg/Documentation/pulls/465
Reviewed-by: Panagiotis "Ivory" Vasilopoulos <git@n0toose.net>
Co-authored-by: Javier Pérez <walpo@noreply.codeberg.org>
Co-committed-by: Javier Pérez <walpo@noreply.codeberg.org>

.gitignore

@@ -1,4 +1,21 @@
-node_modules/
+# Project-specific
+## Output of Eleventy site builder
 _site/
-pages.git/
+
+
+# Integrated development environments (IDEs) and text editors
+## JetBrains
 .idea/
+
+## Visual Studio Code
+.vscode/
+
+
+# Package managers
+## npm - Node.js
+node_modules/
+
+
+# Web servers
+## Codeberg Pages
+pages.git/