rhg: Add an allow-list of ignored extensions Because rhg doesn’t know how a Python extension would affect behavior it implements in Rust, when an unsupported extension is enabled it conservatively falls back to Python-based hg. However many users will have unsupported extensions enabled in practice. Maybe they don’t actually affect rhg behavior, but we don’t know. This adds a `rhg.ignored-extensions` configuration that lets users list extensions that rhg can safely ignore and proceed even if they’re not supported in Rust. Differential Revision: https://phab.mercurial-scm.org/D10188

# 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