.editorconfig

heads: add support for specifying branches by revset

Before this commit, e.g. "hg heads .^" would fail with:

  abort: unknown revision '.^'!

Like the previous patch, I don't care about the command itself (I
don't think I had ever used it before), I'm just cleaning up uses of
repo[<string>].

Differential Revision: https://phab.mercurial-scm.org/D3084

# See http://EditorConfig.org for the specification

root = true

[*.py]
indent_size = 4
indent_style = space
trim_trailing_whitespace = true

[*.{c,h}]
indent_size = 8
indent_style = tab
trim_trailing_whitespace = true