various python neatness cleanups

All changes were created by running

"pyupgrade --py3-only --keep-percent-format"

and committing the results. I have not touched string formatting for
now.

- use set literals
- simplify .format() parameter naming
- remove __future__
- remove default "r" mode for open()
- use OSError rather than compatibility aliases
- remove stray parentheses in function(generator) scopes

1 files changed, 1 insertions, 1 deletions

diff --git a/test cases/windows/12 resources with custom targets/res/gen-res.py b/test cases/windows/12 resources with custom targets/res/gen-res.py
index 2feb02f5b..e5ef6b108 100755
--- a/test cases/windows/12 resources with custom targets/res/gen-res.py
+++ b/test cases/windows/12 resources with custom targets/res/gen-res.py
@@ -2,5 +2,5 @@
 
 import sys
 
-with open(sys.argv[1], 'r') as infile, open(sys.argv[2], 'w') as outfile:
+with open(sys.argv[1]) as infile, open(sys.argv[2], 'w') as outfile:
     outfile.write(infile.read().format(icon=sys.argv[3]))