chore: remove unused _RenameMap class

Dead code - class was defined but never instantiated anywhere.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: dimitri-yatsenko

src/datajoint/table.py

@@ -50,12 +50,6 @@
 )
 
 
-class _RenameMap(tuple):
-    """for internal use"""
-
-    pass
-
-
 @dataclass
 class ValidationResult:
     """