Added and corrected comments

outOfLineContent.go

@@ -13,6 +13,8 @@ type OutOfLineContent struct {
 	SRC  IRI       `xml:"src,attr"`
 }
 
+// newOutOfLineContent creates a new OutOfLineContent. It returns a
+// *OutOfLineContent and an error.
 func newOutOfLineContent(mediaType string, content any) (*OutOfLineContent, error) {
 	if mediaType, _, err := mime.ParseMediaType(mediaType); err != nil {
 		return nil, fmt.Errorf("media type %v incompatible with out of line content", mediaType)
@@ -29,12 +31,19 @@ func newOutOfLineContent(mediaType string, content any) (*OutOfLineContent, erro
 	return &OutOfLineContent{Type: MediaType(mediaType), SRC: content.(IRI)}, nil
 }
 
+// isContent checks whether the OutOfLineContent is a Content. It returns a
+// bool.
 func (o *OutOfLineContent) isContent() bool { return true }
 
+// hasSRC checks whether the OutOfLineContent has a SRC attribute. It returns a
+// bool.
 func (o *OutOfLineContent) hasSRC() bool { return true }
 
+// getType returns the Type of the OutOfLineContent as a string.
 func (o *OutOfLineContent) getType() string { return string(o.Type) }
 
+// Check checks the OutOfLineContent for incompatibilities with RFC4287. It
+// returns an error.
 func (o *OutOfLineContent) Check() error {
 	mediaType := o.getType()