gitlab-advanced-sast-cpp: update SAST docs to include C/C++ support in GitLab Advanced SAST
Problem to solve
In the SAST documentation, C++ is currently listed as supported by standard analyzers (all tiers) but not by GitLab Advanced SAST, as it was still in Beta.
Now that C/C++ support has reached GA, the documentation needs to be updated to reflect this.
Relevant sections to update:
Edited by Hua Yan