Add GerritRobotComments PHPCS report
A PHPCS report to generate JSON files usable as request bodies for the Gerrit robot comment API, which can be used to add PHPCS fixes to Gerrit patches in such a way that users can apply them with a click.
The file is moved here from the mediawiki/tools/codesniffer Gerrit repo, where it was originally added in the patches
- https://gerrit.wikimedia.org/r/c/mediawiki/tools/codesniffer/+/647594
- https://gerrit.wikimedia.org/r/c/mediawiki/tools/codesniffer/+/647595
Bug: T287426