Add support for TypeSpec docs

Since doc's can be added on both the generic declaration (GenDecl) as well as on the type declaration (TypeSpec) we need to check both.
In order to check both declaration we copy the GenDecl docs to the TypeSpec docs if the TypeSpec has no documentation.

parser/parser.go

@@ -21,8 +21,7 @@ type Parser struct {
 type visitor struct {
 	*Parser
 
-	name     string
-	explicit bool
+	name string
 }
 
 func (p *Parser) needType(comments string) bool {
@@ -43,20 +42,33 @@ func (v *visitor) Visit(n ast.Node) (w ast.Visitor) {
 		return v
 
 	case *ast.GenDecl:
-		v.explicit = v.needType(n.Doc.Text())
-
-		if !v.explicit && !v.AllStructs {
-			return nil
+		explicit := v.needType(n.Doc.Text())
+		if !explicit {
+			return v
 		}
+
+		for _, nc := range n.Specs {
+			switch nct := nc.(type) {
+			case *ast.TypeSpec:
+				nct.Doc = n.Doc
+			}
+		}
+
 		return v
 	case *ast.TypeSpec:
+		explicit := v.needType(n.Doc.Text())
+		if !explicit && !v.AllStructs {
+			return nil
+		}
+
 		v.name = n.Name.String()
 
 		// Allow to specify non-structs explicitly independent of '-all' flag.
-		if v.explicit {
+		if explicit {
 			v.StructNames = append(v.StructNames, v.name)
 			return nil
 		}
+
 		return v
 	case *ast.StructType:
 		v.StructNames = append(v.StructNames, v.name)