typing: add type hints to mpatch implementations
Again, using `merge-pyi` to apply the stubs in cext and then manually type the
private methods. The generated stub without these hints inferred very little,
and the stuff it did was wrong.
# 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