Update lab to include reset() call for tags and labels

Author: dpvc

lib/TeX-lab.js

@@ -60,6 +60,8 @@ const Lab = window.Lab = {
     math.end = {node: text, n: 0, delim: ''};
     this.mathItem = math;
 
+    jax.TeX.parseOptions.tags.reset();
+
     handleRetriesFor(function () {
       math.compile();
       this.mml = toMml(math.root);