Highlight repeated function calls in stack traces

[adrhill]

As pointed out in #52334, stack traces of StackOverflowErrors currently don't highlight recursions enough. Spotting the light black (repeats $n times) note in a colorful stack trace is difficult.

This PR highlights this note in bold yellow color.

Examples

Before the PR, the recursion in [4] lu is hard to spot:

After this PR, it is emphasized in bold and yellow color:

[kimikage]

xref: #54712

(I don't see a problem with multiple PRs for the same issue, but I do see a problem with no follow-up for a few days.)

[adrhill]

Might be worth cross-referencing my original post in the #gripes Slack channel.
I looked through open issues like #52334 but didn't expect @xlxs4 to have opened PR #54712 in the meantime.

[kimikage]

In fact, these two PRs are different. In short, the colors are different.

I am not interested in bike-shedding. I am just wondering if Base.warn_color() or Base.error_color() could be used instead of hardcoding colors.
(This is in Base and the functions might not be available depending on the order of loading.)

[LilithHafner]

This does not fix #52334, but is an improvement (except that sometimes the number this PR highlights is wrong, but that's a separate bug). I picked this one over #54712 to avoid hardcoding colors.