[issue21054] Improve indexing of syntax symbols

[Terry J. Reedy]

Changes by Terry J. Reedy <tjreedy at udel.edu>:


----------
dependencies: +Derby: Convert the _sre module to use Argument Clinic, Index (augmented) assignment symbols

_______________________________________
Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue21054>
_______________________________________