Renames symbols.
Currently only supports renaming to a symbol with a monotonic increasing suffix.
Change-Id: I7ae67a7b1740ac0e83c1821643cf7b8b1959f84d
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/42842
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: James Price <jrprice@google.com>