fileset: combine union of basic patterns into single matcher
This appears to improve query performance in a big repository than I thought.
Writing less Python in a hot loop, faster computation we gain.
$ hg files --cwd mozilla-central --time 'set:a* + b* + c* + d* + e*'
(orig) time: real 0.670 secs (user 0.640+0.000 sys 0.030+0.000)
(new) time: real 0.210 secs (user 0.180+0.000 sys 0.020+0.000)
BasedOnStyle: LLVM
IndentWidth: 8
UseTab: ForIndentation
BreakBeforeBraces: Linux
AllowShortIfStatementsOnASingleLine: false
IndentCaseLabels: false
AllowShortBlocksOnASingleLine: false
AllowShortFunctionsOnASingleLine: false
IncludeCategories:
- Regex: '^<'
Priority: 1
- Regex: '^"'
Priority: 2