The file format for each option now features a "Example:" header that
can provide one or more examples that get rendered appropriately in the
output. All options MUST have at least one example or gen.pl complains
at build-time.
This fix also does a few other minor format and consistency cleanups.
Closes#7654
We currently use both spellings the british "behaviour" and the american
"behavior". However "behavior" is more used in the project so I think
it's worth dropping the british name.
Closes#6395
