This is the first installment of a multi-PR series significantly
refactoring how highlights are being specified.
The end goal is to have a base set of 20 ish most common highlights,
and then specific files only need to add more groups to that as needed.
As a complicating factor, we also want to migrate to the new default
color scheme eventually. But by sharing a base set, that future PR
will hopefully be a lot smaller since a lot of tests will be migrated
just simply by updating the base set in place.
As a first step, fix the anti-pattern than Screen defaults to ignoring
highlights. Highlights are integral part of the screen state, not
something "extra" which we only test "sometimes". For now, we still
allow opt-out via the intentionally ugly
screen._default_attr_ids = nil
The end goal is to get rid of all of these eventually (which will be
easier as part of the color scheme migration)
This is the command invoked repeatedly to make the changes:
:%s/^\(.*\)|\%(\*\(\d\+\)\)\?$\n\1|\%(\*\(\d\+\)\)\?$/\=submatch(1)..'|*'..(max([str2nr(submatch(2)),1])+max([str2nr(submatch(3)),1]))/g
