scripts/setlocalversion: also consider annotated tags of the form vx.y.z-${file_localversion}

Commit 6ab7e1f9 ("setlocalversion: use only the correct release
tag for git-describe") was absolutely correct to limit which annotated
tags would be used to compute the -01234-gabcdef suffix. Otherwise, if
some random annotated tag exists closer to HEAD than the vX.Y.Z one,
the commit count would be too low.

However, since the version string always includes the
${file_localversion} part, now the problem is that the count can be
too high. For example, building an 6.4.6-rt8 kernel with a few patches
on top, I currently get

$ make -s kernelrelease
6.4.6-rt8-00128-gd78b7f406397

But those 128 commits include the 100 commits that are in
v6.4.6..v6.4.6-rt8, so this is somewhat misleading.

Amend the logic so that, in addition to the linux-next consideration,
the script also looks for a tag corresponding to the 6.4.6-rt8 part of
what will become the `uname -r` string. With this patch (so 29 patches
on top of v6.4....