The `outline-none` rule should catch more cases

[EvgenyOrekhov]

The outline-none rule should generate a warning for the following case:

:focus {
    outline: transparent;
}

Also, it should generate warnings for any values that use either 0, none, or transparent, e. g.

:focus {
    outline: 1px none;
}
:focus {
    outline: 0 red;
}
:focus {
    outline: 1px solid transparent;
}
// and other combinations and permutations

[EvgenyOrekhov]

I am no longer interested in this. Feel free to reopen if needed.