bpo-39663: IDLE: Add additional tests for pyparse (GH-18536)

Test when find_good_parse_start should return 0.

Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>
diff --git a/Lib/idlelib/NEWS.txt b/Lib/idlelib/NEWS.txt
index 8381209..021e1f7 100644
--- a/Lib/idlelib/NEWS.txt
+++ b/Lib/idlelib/NEWS.txt
@@ -3,6 +3,8 @@
 ======================================
 
 
+bpo-39663: Add tests for pyparse find_good_parse_start().
+
 bpo-39600: Remove duplicate font names from configuration list.
 
 bpo-38792: Close a shell calltip if a :exc:`KeyboardInterrupt`