black: merge config into main pyproject.toml now that we have it
This means that naive contributors who just run `black` on a source file
will get reasonable behavior as long as they have a recent black. Yay!
Differential Revision: https://phab.mercurial-scm.org/D9834
BasedOnStyle: LLVM
IndentWidth: 8
UseTab: ForIndentation
BreakBeforeBraces: Linux
AllowShortIfStatementsOnASingleLine: false
IndentCaseLabels: false
AllowShortBlocksOnASingleLine: false
AllowShortFunctionsOnASingleLine: false
IncludeCategories:
- Regex: '^<'
Priority: 1
- Regex: '^"'
Priority: 2