When we try to lowercase register names (e.g. Q0 -> q0) we avoid
doing that for parts of the code that are comments, as comments
occasionally contain pseudocode that contain such mentions that
aren't register names, but pseudocode/reference code variables.
See 7ebb6c54eb for more details
about that.
In addition to recognizing comments starting with //, also
recognize /* and @ (which is a comment char in arm assembly, but
not in aarch64).
Martin Storsjö
cd7a3cd799