revset: introduce and use _revsbetween This is similar in spirit to revlog.nodesbetween, but less ambitious, much simpler, and ~2x faster.

revset: implement dagrange directly This is much faster than the older implementation (~8x).

revset: turn dagrange into a function

revset: drop unreachable code

perf: add a benchmark for revrange

test-tags: enable for Windows It turns out that MSYS does have a chmod.exe, but it has no effect. So, the inserted "#if unix-permissions" is somewhat redundant, as the test would pass without it as well: it would simply write the tag cache, despite what the comment says. But I'm actually in favor of inserting the #if, as it makes it clearer what's going on.

tests: roll test-copy2.t into test-copy.t

help: fix keyword search output for extension commands This patch fixes the help keyword search "hg help -k" to show correct results in the section listing extension commands.