PLT-1424 Added XRegExp library to fix search highlighting (#3787)

webapp/package.json

@@ -31,7 +31,8 @@
     "react-textarea-autosize": "4.0.3",
     "superagent": "2.1.0",
     "twemoji": "2.0.5",
-    "velocity-animate": "1.2.3"
+    "velocity-animate": "1.2.3",
+    "xregexp": "3.1.1"
   },
   "devDependencies": {
     "babel-core": "6.13.2",