Update VSCode settings

- add .rst files to be scanned by grammarly for spell checking and
  grammar checking.

Change-Id: I4c231230431183417bf621ba91fc4b298a2cc328
Reviewed-by: Cristian Maureira-Fredes <[email protected]>

Author: ShyamQt

.vscode/settings.json

@@ -15,5 +15,6 @@
     "python.testing.unittestEnabled": true,
     "flake8.args": [
         "--config=.flake8"
-    ]
+    ],
+    "grammarly.files.include": ["**/*.rst", "**/*.md"],
 }