Normalize focused goal output

Merge the "1 focused goal" line with the subsequent "(shelved: 1)" line,
since this is the new output in Coq 8.15+.

std++ does not currently produce this output, since no test calls `Show`
with shelved goals, but this future-proofs the test normalization.
2 jobs for !330 with adjust-focused-goal in 11 minutes and 22 seconds (queued for 2 seconds)
merge request