docs: add refactor warning to CONTRIBUTING.md

Author: CyanVoxel

CONTRIBUTING.md

@@ -1,6 +1,6 @@
 # Contributing to TagStudio
 
-_Last Updated: November 19th, 2024_
+_Last Updated: December 12th, 2024_
 
 Thank you so much for showing interest in contributing to TagStudio! Here are a set of instructions and guidelines for contributing code or documentation to the project. This document will change over time, so make sure that your contributions still line up with the requirements here before submitting a pull request.
 
@@ -14,6 +14,7 @@ Thank you so much for showing interest in contributing to TagStudio! Here are a
 -   Check the [Feature Roadmap](/docs/updates/roadmap.md) page to see what priority features there are, the [FAQ](/README.md/#faq), as well as the open [Issues](https://github.com/TagStudioDev/TagStudio/issues) and [Pull Requests](https://github.com/TagStudioDev/TagStudio/pulls).
 -   If you'd like to add a feature that isn't on the feature roadmap or doesn't have an open issue, **PLEASE create a feature request** issue for it discussing your intentions so any feedback or important information can be given by the team first.
     -   We don't want you wasting time developing a feature or making a change that can't/won't be added for any reason ranging from pre-existing refactors to design philosophy differences.
+- **Please don't** create pull requests that consist of large refactors, *especially* without discussing them with us first. These end up doing more harm than good for the project by continuously delaying progress and disrupting everyone else's work.
 -   If you wish to discuss TagStudio further, feel free to join the [Discord Server](https://discord.com/invite/hRNnVKhF2G)
 
 ### Contribution Checklist