Update broken link to RTD docs in comment

Author: tetrapod00

conf.py

@@ -179,7 +179,7 @@
 
 html_title = supported_languages[language] % ( "(" + version + ")" )
 
-# VCS options: https://docs.readthedocs.io/en/latest/vcs.html#github
+# Edit on GitHub options: https://docs.readthedocs.io/en/latest/guides/edit-source-links-sphinx.html
 html_context = {
     "display_github": not is_i18n,  # Integrate GitHub
     "github_user": "godotengine",  # Username