Show full list of supported VCS scheme in error message
Show full list of supported VCS scheme in error message

When an editable requirement is neither a local directory nor
a URL with a supported VCS scheme, we show the full list
of supported VCS schemes in the error message.

sbidoul/pip,pradyunsg/pip,pfmoore/pip,pradyunsg/pip,pypa/pip,sbidoul/pip,pfmoore/pip,pypa/pip