Update CONTRIBUTING.md

Replaced a few more links, squash me

CONTRIBUTING.md

@@ -3,7 +3,7 @@
 This document summarizes the most important points for people interested in
 contributing to Redot, especially via bug reports or pull requests.
 
-The [Redot Discord](https://discord.gg/redot) documentation has a dedicated Contributing section
+The [Redot Documentation](https://docs-stable.redotengine.org/contributing/development) has a dedicated Contributing section
 which details these points and more, and is a recommended read.
 
 ## Table of contents
@@ -41,7 +41,8 @@ call a _regression_), please mention it and clarify which versions you tested
 
 **The main issue tracker is for bug reports and does not accept feature proposals.**
 
-Instead, head to the [Redot Discord](https://discord.gg/redot).
+Visit the [Redot Proposals Repo](https://github.com/Redot-Engine/redot-proposals)
+to suggest features or improvements to the engine.
 
 ## Contributing pull requests
 
@@ -70,7 +71,8 @@ Similar rules can be applied when contributing bug fixes - it's always best to
 discuss the implementation in the bug report first if you are not 100% about
 what would be the best fix.
 
-Visit the [Redot Discord](https://discord.gg/redot) for information and guides related to contribution and pull requests.
+Read the [Redot Documentation](https://docs-stable.redotengine.org/contributing/development)
+for information and guides related to contribution and pull requests.
 
 ### Be mindful of your commits
 
@@ -198,7 +200,8 @@ or a bug you want to fix), the following channels can be used:
   existing issue about a topic you want to discuss, you can participate directly.
   If not, you can open a new issue. Please mind the guidelines outlined above
   for bug reporting.
-- Feature Proposals should be made on the [Redot Proposals Repo](https://github.com/Redot-Engine/redot-proposals).
+- [Redot Proposals Repo](https://github.com/Redot-Engine/redot-proposals): Feature
+or improvement proposals.
 - [Redot](https://x.com/redotengine) on Twitter
 
 Thanks for your interest in contributing!