doc: use American spellings per style guide
Getting kind of trivial here, won't mind if this gets rejected for too much churn, although the README.md
change at least should land, so I figure why not do all the instances...It's not that many files.
¯\(ツ)/¯
Checklist
-
make -j4 test
(UNIX), orvcbuild test
(Windows) passes -
documentation is changed or added -
commit message follows commit guidelines
Affected core subsystem(s)
doc