GeezerVison

Fixes #140764

Summary

Makes the syntax warning hint clearer when detecting potentially missing commas in sequence literals.

Problem

Current warning: 'int' object is not subscriptable; perhaps you missed a comma?

This hint can be cryptic - it's not immediately obvious that it's suggesting the code might have been meant as separate items in a sequence.

Solution

New warning: 'int' object is not subscriptable; did you miss a comma to separate sequence elements?

Example

# Before:
>>> lambda: 1[2]
<input>:1: SyntaxWarning: 'int' object is not subscriptable; perhaps you missed a comma?

# After:
>>> lambda: 1[2]
<input>:1: SyntaxWarning: 'int' object is not subscriptable; did you miss a comma to separate sequence elements?

Much clearer what the intended fix might be!

Changes

• Updated 3 warning messages in Python/codegen.c:
  • Callable check
  • Subscriptable check
  • Index type check
• Updated corresponding test regex patterns in Lib/test/test_grammar.py

Test Plan

• All existing tests updated to match new message
• Warning still triggers in same cases, just with clearer text
• No behavioral changes, only message improvement

• Issue: Make "perhaps you missed a comma?" hint in syntax warnings less cryptic #140764