git add: --ignore-removal is a better named --no-all
In the historical context of "git add --all ." that pays attention
to "all kinds of changes" (implying "without ignoring removals"),
the option to countermand it "--no-all" may have made sense, but
because we will be making "--all" the default when a pathspec is
given, it makes more sense to rename the option to a more explicit
"--ignore-removal". The "--all" option naturally becomes its
negation, "--no-ignore-removal".