Update Documentation/GeneralConventions/ReadmeFile.rst

Co-authored-by: Chris Müller <[email protected]>

Documentation/GeneralConventions/ReadmeFile.rst

@@ -9,7 +9,7 @@
 
 Full documentation contains both a :file:`README.rst` and a :file:`Documentation/Index.rst`
 file. To avoid redundancy in both places, the :file:`README.rst` in this case usually
-contains only a summary and links to all aspects of the project, i.e. the VCS
+contains only a summary and links to all aspects of the project, i.e. the :abbr:`VCS (Version Control System)`
 repository, the published documentation and - if available - the TYPO3 Extension
 Repository (TER) page to guide the reader to the next steps. This could be for
 example: