revset: added lazyset implementation to desc revset
Performance benchmarking:
$ time hg log -qr "first(desc(hg))"
changeset: 0:
9117c6561b0b
real 0m2.210s
user 0m2.158s
sys 0m0.049s
$ time ./hg log -qr "first(desc(hg))"
changeset: 0:
9117c6561b0b
real 0m0.171s
user 0m0.131s
sys 0m0.035s
Minimal hgk check
$ echo "[extensions]" >> $HGRCPATH
$ echo "hgk=" >> $HGRCPATH
$ hg init repo
$ cd repo
$ echo a > a
$ hg ci -Am adda
adding a
$ hg debug-cat-file commit 0
tree a0c8bcbbb45c
parent 000000000000
author test 0 0
revision 0
branch default
phase draft
adda
$ cd ..