[issue28128] Improve the warning message for invalid escape sequences

[Serhiy Storchaka]

Serhiy Storchaka added the comment:

The basic concept LGTM.

first_invalid_escape_char is redundant, it is just s[first_invalid_escape_idx]. Or maybe better to return a pointer instead of an index.

bytes literals need similar solution.

----------

_______________________________________
Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue28128>
_______________________________________