extension: add a `required` suboption to enforce the use of an extensions
If `required` is set, failing to load an extensions will abort. See the test
and documentation for details.
Differential Revision: https://phab.mercurial-scm.org/D11822
# 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