.editorconfig

files: extract code for extra filtering of the `removed` entry into copies

We want to reduce the set of `removed` files that to the set of files actually
removed. That `removed` set is used as of the changeset centric algorithm,
having smaller sets means less processing and faster computation.

In this changeset we extract the code to be a function of it own. We will make
use of it in the next changesets.

Differential Revision: https://phab.mercurial-scm.org/D8588

# 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