bpo-32989: IDLE - remove unneeded parameter (GH-18138)

IDLE does not pass a non-default _synchre in any of its calls to
pyparse.find_good_parse_start.

Author: terryjreedy

Lib/idlelib/NEWS.txt

@@ -6,7 +6,8 @@ Released on 2020-10-05?
 bpo-39050: Make Settings dialog Help button work again.
 
 bpo-32989: Add tests for editor newline_and_indent_event method.
-Remove dead code from pyparse find_good_parse_start method.
+Remove unneeded arguments and dead code from pyparse
+find_good_parse_start method.
 
 bpo-38943: Fix autocomplete windows not always appearing on some
 systems.  Patch by Johnny Najera.

Lib/idlelib/pyparse.py

@@ -133,7 +133,7 @@ def set_code(self, s):
         self.code = s
         self.study_level = 0
 
-    def find_good_parse_start(self, is_char_in_string, _synchre=_synchre):
+    def find_good_parse_start(self, is_char_in_string):
         """
         Return index of a good place to begin parsing, as close to the
         end of the string as possible.  This will be the start of some