tags-cache: add a dedicated warm cache function to hgtagsfnodescache
Having a dedicated API point will help to optimize that specific usage. Right
doing a full phases weam takes a long time, even when the cache is already
filled.
$ hg init repo
$ cd repo
$ touch unknown
$ touch a
$ hg add a
$ hg ci -m "1"
$ touch b
$ hg add b
$ hg ci -m "2"
Should show unknown
$ hg status
? unknown
$ hg revert -r 0 --all
removing b
Should show unknown and b removed
$ hg status
R b
? unknown
Should show a and unknown
$ ls -A
.hg
a
unknown