revsets: add commonancestors revset
This is a method to reproduce "::x and ::y" such that a set can be sent
in. For instance, it'd be convenient to have "::heads()" work like this
but that already means "::x + ::y + ..." for each element in the
"heads()" set.
Therefore, we add the "commonancestors" method to mean "::x and ::y ..."
for each head in the given set.
BasedOnStyle: LLVM
IndentWidth: 8
UseTab: ForIndentation
BreakBeforeBraces: Linux
AllowShortIfStatementsOnASingleLine: false
IndentCaseLabels: false
AllowShortBlocksOnASingleLine: false
AllowShortFunctionsOnASingleLine: false
IncludeCategories:
- Regex: '^<'
Priority: 1
- Regex: '^"'
Priority: 2