chore: drop label comments across scripts

CommentsSayWhy read three scripts while 22 comments in 13 other files
named the next statement. They are removed or replaced by the reason,
and the test reads every tracked script and install.py.

scripts/dedup.py

@@ -291,7 +291,6 @@ def deduplicate(bios_dir: str, dry_run: bool = False) -> dict:
     if not dry_run and empty_cleaned:
         print(f"Cleaned {empty_cleaned} empty directories")
 
-    # Write MAME clone mapping
     if mame_clones:
         # A group is only visible while both copies are on disk, and this run
         # has just deleted the clone. Writing only what was seen this time