IDLE: replace if statement with expression (GH-94228)

(cherry picked from commit 91f9947)

Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>

Lib/idlelib/iomenu.py

@@ -13,14 +13,10 @@
 from idlelib.util import py_extensions
 
 py_extensions = ' '.join("*"+ext for ext in py_extensions)
-
 encoding = 'utf-8'
-if sys.platform == 'win32':
-    errors = 'surrogatepass'
-else:
-    errors = 'surrogateescape'
+errors = 'surrogatepass' if sys.platform == 'win32' else 'surrogateescape'
+
 
-
 class IOBinding:
 # One instance per editor Window so methods know which to save, close.
 # Open returns focus to self.editwin if aborted.