This error was only returned in a single location, and not used anywhere
as a specific type.
The error returned by `validateNoScheme()` also appeared to only be used in
one case; in all other cases, the error itself was ignored, and replaced with
a custom error. Because of this, this patch also replace `validateNoScheme()`
with a `hasScheme()` function that returns a boolean, to better match how it's
used.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
98202c86ad