text: return error on constructor

Blocked by #102

src/dom/text.zig

@@ -38,6 +38,16 @@ pub const Text = struct {
     pub const prototype = *CharacterData;
     pub const mem_guarantied = true;
 
+    // TODO add constructor, but I need to associate the new Text
+    // with the current document global object...
+    // > The new Text(data) constructor steps are to set this’s data to data
+    // > and this’s node document to current global object’s associated
+    // > Document.
+    // https://dom.spec.whatwg.org/#dom-text-text
+    pub fn constructor() !*parser.Comment {
+        return error.NotImplemented;
+    }
+
     // JS funcs
     // --------