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/doc/gendoc.py	Mon Jan 06 01:44:46 2025 -0500
+++ b/doc/gendoc.py	Tue Jan 07 17:28:46 2025 -0500
@@ -361,7 +361,7 @@
 
 def _rendertpl(tplname, data):
     tplpath = os.path.join(os.path.dirname(__file__), 'templates', tplname)
-    with open(tplpath, 'r') as f:
+    with open(tplpath) as f:
         tpl = f.read()
 
     if isinstance(tpl, bytes):