.editorconfig

docs: describe ui.color consistently with --color

The --color option is described to accept "boolean, always, auto,
never, or debug". Let's use a similar description for ui.color. Also
fix the formatting to use double quotes as we seem to use for about
half the values in config.txt (the other half uses double
backticks). Also use uppercase Boolean for consistency within the
file.

# 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