MakeVFSPath violates URL standards

[puellanivis]

According to RFC 3986 Section 3 if a URI contains :// then it must have an authority and an path-abempty. This means that at minimum it must either be scheme:// or scheme:///. Alternative, a URI may consist of a path without an authority wherein it is only prefixed by a scheme: and may not start with // thus guaranteeing that a scheme+path URI cannot be mistake for a scheme+authority+path URI. This is while file: scheme URLs have three slashes at the start, example: file:///path/to/local/filename.

The way MakeVFSPath is written, it either prefixes vfs:// to a relative path, or replaces the leading / of an absolute path with vfs://, both of which produce invalid URIs.