docs(testing): tech edits

Author: kapunahelewong

public/docs/ts/latest/guide/_data.json

@@ -184,7 +184,7 @@
 
   "testing": {
     "title": "Testing",
-    "intro": "Techniques and practices for testing an Angular app"
+    "intro": "Techniques and practices for testing an Angular app."
   },
 
   "typescript-configuration": {