.editorconfig

helptext: mention in `hg help config` that `.hg/hgrc-not-shared` is consulted

Recently we added `.hg/hgrc-not-shared` which is a config file which won't be
shared with shares when share-safe mode is enabled. Irrespective of whether
we are using share-safe or not, we consult this file now.

Let's document that.

Differential Revision: https://phab.mercurial-scm.org/D9412

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

root = true

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

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

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