.editorconfig

grep: add --diff flag

Adds a diff flag, which works exactly same as all, in fact since
--all searches diffs, there diff is a better name for it.
The all flag is still here for backward compatibility reasons.
Some major tests for all has been picked and added for diff.

Differential Revision: https://phab.mercurial-scm.org/D3763

# 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

[*.t]
indent_size = 2
indent_style = space
trim_trailing_whitespace = false