spelling fixes

patch contains some spelling fixes ( just in comments ) as found by a bot ( https://github.com/ka7/misspell_fixer ). Any upcoming License changes (e.g. GPL2 to GPL3+) are hereby granted.

Please note:
Checked the full source, and found overall ~ 2.5k potential ones in about 1k files. ( the script is sometimes just stupid and creates false-positives, or rename variables.. I'm after the # comments, readme, .. - stuff that don't break your project. ).
Anyway, that's a bunch of changes - so here this is a first try to check your reaction. Maybe you want to keep sources if possible similar to mysql, the changes will take some time to review, ... also maybe just 1 big patch or 10 smaller ones; a GH-pull-request or a mail with .patch
For testing I do "make; make test" to changed source in a docker environment. So should not introduce issues.