idlelib: replace 'while 1' with 'while True' (GH-94827)

(cherry picked from commit 6a15f918b5)

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

Lib/idlelib/editor.py

@@ -1301,7 +1301,7 @@ def smart_backspace_event(self, event):
         want = ((have - 1) // self.indentwidth) * self.indentwidth
         # Debug prompt is multilined....
         ncharsdeleted = 0
-        while 1:
+        while True:
             chars = chars[:-1]
             ncharsdeleted = ncharsdeleted + 1
             have = len(chars.expandtabs(tabwidth))