Use form tags when available (#1422)

* Add support for form tags

---------

Co-authored-by: Philip Constantinou <phil@Philips-MacBook-Pro-3.local>

field_parser.go

@@ -67,13 +67,20 @@ func (ps *tagBaseFieldParser) ShouldSkip() bool {
 
 func (ps *tagBaseFieldParser) FieldName() (string, error) {
 	var name string
+
 	if ps.field.Tag != nil {
 		// json:"tag,hoge"
 		name = strings.TrimSpace(strings.Split(ps.tag.Get(jsonTag), ",")[0])
 
 		if name != "" {
 			return name, nil
 		}
+
+		// use "form" tag over json tag
+		name = strings.TrimSpace(strings.Split(ps.tag.Get(formTag), ",")[0])
+		if name != "" {
+			return name, nil
+		}
 	}
 
 	if ps.field.Names == nil {

operation.go

@@ -372,6 +372,7 @@ func (operation *Operation) ParseParamComment(commentLine string, astFile *ast.F
 }
 
 const (
+	formTag             = "form"
 	jsonTag             = "json"
 	bindingTag          = "binding"
 	defaultTag          = "default"