pyupgrade: drop redundant `open()` modes On one hand, this gets rid of some py2 cruft (like `U` and `t` modes). OTOH, I like being explict. But there's no way to disable individual transformations (and this change is part of `_fix_tokens()`, which is even harder to selectively use locally), and I'd rather have less noise when using `pyupgrade`. Warning: `contrib/synthrepo.py` appears not to have been updated to py3, as it's passing str to `error.Abort`. But since it was opening the file in unicode on py2, this change is a no-op.

--- a/hgext/convert/common.py	Mon Jan 06 01:44:46 2025 -0500
+++ b/hgext/convert/common.py	Tue Jan 07 17:28:46 2025 -0500
@@ -90,7 +90,7 @@
     whitespace: Optional[bytes] = None,
 ):
     if data is None:
-        data = open(filepath, 'r', encoding='latin1')
+        data = open(filepath, encoding='latin1')
     else:
         if filepath is not None:
             raise error.ProgrammingError(