docs: remove code snippet and 'Stackdriver' (#71)

Remove the code snippet which is untested. Fixes #70. Also remove 'Stackdriver' from the README.

Author: busunkim96

README.rst

@@ -1,10 +1,10 @@
-Python Client for Stackdriver Monitoring API
+Python Client for Cloud Monitoring API
 =======================================================
 
 |ga| |pypi| |versions| 
 
-`Stackdriver Monitoring API`_: Manages your Stackdriver Monitoring data and
-configurations. Most projects must be associated with a Stackdriver account,
+`Cloud Monitoring API`_: Manages your Cloud Monitoring data and
+configurations. Most projects must be associated with a Google Cloud account,
 with a few exceptions as noted on the individual method pages.
 
 - `Client Library Documentation`_
@@ -16,7 +16,7 @@ with a few exceptions as noted on the individual method pages.
    :target: https://pypi.org/project/google-cloud-monitoring/
 .. |versions| image:: https://img.shields.io/pypi/pyversions/google-cloud-monitoring.svg
    :target: https://pypi.org/project/google-cloud-monitoring/
-.. _Stackdriver Monitoring API: https://cloud.google.com/monitoring/api/ref_v3/rest/
+.. _Cloud Monitoring API: https://cloud.google.com/monitoring/api/ref_v3/rest/
 .. _Client Library Documentation: https://googleapis.dev/python/monitoring/latest
 .. _Product Documentation:  https://cloud.google.com/monitoring/docs
 
@@ -27,12 +27,12 @@ In order to use this library, you first need to go through the following steps:
 
 1. `Select or create a Cloud Platform project.`_
 2. `Enable billing for your project.`_
-3. `Enable the Stackdriver Monitoring API.`_
+3. `Enable the Cloud Monitoring API.`_
 4. `Setup Authentication.`_
 
 .. _Select or create a Cloud Platform project.: https://console.cloud.google.com/project
 .. _Enable billing for your project.: https://cloud.google.com/billing/docs/how-to/modify-project#enable_billing_for_a_project
-.. _Enable the Stackdriver Monitoring API.:  https://cloud.google.com/monitoring/api/enable-api
+.. _Enable the Cloud Monitoring API.:  https://cloud.google.com/monitoring/api/enable-api
 .. _Setup Authentication.: https://googleapis.dev/python/google-api-core/latest/auth.html
 
 Installation
@@ -81,37 +81,12 @@ Windows
     <your-env>\Scripts\activate
     <your-env>\Scripts\pip.exe install google-cloud-monitoring
 
-Preview
-~~~~~~~
-
-MetricServiceClient
-^^^^^^^^^^^^^^^^^^^
-
-.. code:: py
-
-    from google.cloud import monitoring_v3
-
-    client = monitoring_v3.MetricServiceClient()
-
-    name = client.project_path('[PROJECT]')
-
-
-    # Iterate over all results
-    for element in client.list_monitored_resource_descriptors(name):
-        # process element
-        pass
-
-    # Or iterate over results one page at a time
-    for page in client.list_monitored_resource_descriptors(name).pages:
-        for element in page:
-            # process element
-            pass
 
 Next Steps
 ~~~~~~~~~~
 
 
--  Read the `Client Library Documentation`_ for Stackdriver Monitoring API
+-  Read the `Client Library Documentation`_ for Cloud Monitoring API
    to see other available methods on the client.
 -  Read the `Product documentation`_ to learn more about the product and see
    How-to Guides.