Return UnmarshalText error (#2)

Co-authored-by: Crow Crowcrow <crow@fuyu.moe>
Co-committed-by: Crow Crowcrow <crow@fuyu.moe>

forms.go

@@ -48,7 +48,11 @@ func decode(form Values, rv reflect.Value, prefix string) error {
 				continue
 			}
 
-			tu.UnmarshalText([]byte(v[0]))
+			err := tu.UnmarshalText([]byte(v[0]))
+			if err != nil {
+				return err
+			}
+
 			continue
 		}