`py-indent-tabs-mode-off' docu typo

Thanks Paul Curry reporting it
Redundancy in py-execute-ge24.3 removed
Execute-region_statement-runs-full-file, lp:1269855
`abbrevs-changed' t when starting, lp:1270631

fixed
Keep previous state of `abbrevs-changed', lp:1270631
`py-end-of-top-level' fixed

CREDITS updated