fix: add support for string concatenation in attributes (#1077)

Author: NorthBlue333

src/lexer/attribute.js

@@ -43,6 +43,7 @@ module.exports = {
       case "<":
       case ">":
       case "!":
+      case ".":
         return this.consume_TOKEN();
       case "[":
         this.attributeListDepth[this.attributeIndex]++;