Add warning to contributing docs (#1417)

Author: evroon

CONTRIBUTING.md

@@ -3,3 +3,7 @@
 Thanks for your interest in contributing to Bracket. Contributions are greatly appreciated!
 
 Please see the [contributing docs](https://docs.bracketapp.nl/docs/community/contributing/) for more information.
+
+> [!IMPORTANT]
+>
+> Note: please open an issue first before creating non-trivial PRs.

docs/content/community/contributing.mdx

@@ -2,6 +2,8 @@
 title: Contributing
 ---
 
+import {Callout} from 'nextra/components'
+
 # Contributing
 
 If you're using Bracket and would like to help support its development, that would be greatly
@@ -32,6 +34,25 @@ Rename the directory to the name of your locale, and start translating the `comm
 the directory. It might be useful to use an online tool (Google `translate json file`) to do the
 translation for you, and then carefully check and correct any mistakes.
 
+## Code contributions
+
+Code contributions are welcome! Please make sure to adhere to the following when submitting a pull
+request:
+
+- Limit Pull Request (PR) size: Aim for small PRs (around 300 lines) that focus on a single,
+  clear task. This makes them faster to review and more likely to be merged.
+- Write clear, descriptive titles.
+- Test your code changes thoroughly.
+
+<Callout type="warning">
+Before making a pull request of something that's not trivial, please open an issue to discuss it
+first. Often there's a simpler way to achieve a certain goal or the scope of Bracket will be too
+large to maintain if every type of feature gets added.
+
+Smaller changes like small bug fixes or documentation improvements can be made without opening
+an issue first.
+</Callout>
+
 ## Contributors
 
 See [README](https://github.com/evroon/bracket).