Update CONTRIBUTING.md

This PR clarifies the update of documentation pages, see https://github.com/mrdoob/three.js/pull/20975#issuecomment-752919076.

.github/CONTRIBUTING.md

@@ -65,7 +65,7 @@ When you’ve decided to make changes, start with the following:
 
 * Don't include any build files to your commit.
 * Not all new features will need a new example. Simpler features could be incorporated into an existing example. Bigger features may be asked to add an example demonstrating the feature.
-* Making changes may require changes to the documentation. If so, please make a new PR for the appropriate doc changes. To update the Chinese docs, simply copy the English to begin with.
+* Making changes may require changes to the documentation. To update the docs in other languages, simply copy the English to begin with.
 * it's good to also add an example and screenshot for it, for showing how it's used and for end-to-end testing.
 * If you modify existing code, run relevant examples to check they didn't break and there wasn't performance regress.
 * If you add some assets for the examples (models, textures, sounds, etc), make sure they have a proper license allowing for their use here, less restrictive the better. It is unlikely for large assets to be accepted.