revset: introduce an API that avoids `formatspec` input serialization Instead of having the data fully serialized, the input can be directly inserted in the tree at a later stage. Just using it for simple "%ld" case provide a significant boost. For example here are the impact on a sample discovery run between two pypy repositories with arbitrary differences (using hg perfdiscovery). $ hg perfdiscovery before: ! wall 0.700435 comb 0.710000 user 0.700000 sys 0.010000 (median of 15) after: ! wall 0.501305 comb 0.510000 user 0.490000 sys 0.020000 (median of 20)