reference: ParseDockerRef: slight refactor, and update docs

- improve documentation
- remove redundant error-check
- simplify interface matching, which slightly improves readability
- touch-up some docs

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

reference/helpers.go

@@ -32,7 +32,7 @@ func FamiliarString(ref Reference) string {
 }
 
 // FamiliarMatch reports whether ref matches the specified pattern.
-// See https://godoc.org/path#Match for supported patterns.
+// See [path.Match] for supported patterns.
 func FamiliarMatch(pattern string, ref Reference) (bool, error) {
 	matched, err := path.Match(pattern, FamiliarString(ref))
 	if namedRef, isNamed := ref.(Named); isNamed && !matched {