Problem statement: When given a line that contained a lot of matches of
your hyperlink regex of choice (thanks to #40305), we would look for
matches
that intersected with currently hovered point. This is *hella*
expensive, because we would re-walk the whole alacritty grid for each
match. With the repro that Joseph shared, we had to go through 4000 such
matches on each frame render.

Problem solution: We now convert the hovered point into a range within
the line (byte-wise) in order to throw away matches that do not
intersect the
hovered range. This lets us avoid performing the unnecessary conversion
when we know it's never going to yield a match range that intersects the
hovered point.

Release Notes:

- terminal: Fixed performance regression when handling long lines.

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Co-authored-by: Dave Waggoner <waggoner.dave@gmail.com>