pub const USER_CONFIG_NAMES: [&str; 2];Expand description
One rung of the discovery chain: the spellings that name the SAME logical
file. Two spellings because .yml and .yaml are both idiomatic and
guessing wrong should not mean silence — a config file the tool ignores is
the worst outcome of the three.
The user rung, under $XDG_CONFIG_HOME (else ~/.config): defaults that
follow the person, not the checkout.