filemerge: when merge tool uses $output, don't leave markers in $local
As explained in the previous patch, we incorrectly leave conflict
markers in both `$local` and `$output` since D12190. I don't
understand why it broke but the fix is simple and clear after all the
recent refactoring.
Differential Revision: https://phab.mercurial-scm.org/D12379
BasedOnStyle: LLVM
IndentWidth: 8
UseTab: ForIndentation
BreakBeforeBraces: Linux
AllowShortIfStatementsOnASingleLine: false
IndentCaseLabels: false
AllowShortBlocksOnASingleLine: false
AllowShortFunctionsOnASingleLine: false
IncludeCategories:
- Regex: '^<'
Priority: 1
- Regex: '^"'
Priority: 2