Add a description of a version-sorting algorithm. (This algorithm does
not precisely match `strverscmp`; it's intentionally simpler in its
handling of leading zeroes, and produces a result easier for humans to
easily understand and do by hand.)

Change all references to sorting to use version-sorting.

Change all references to "ASCIIbetically" to instead say "sort
non-lowercase before lowercase".

Treat numeric chunks with equal value but differing numbers of leading
zeroes as equal, unless we get to the end of the entire string in which
case we use "more leading zeroes in the earliest differing chunk" as a
tiebreaker.

Treat `_` as a word separator, sorting it before anything other than
space.

Give more examples.