Change snippits.py to need less altering when copy and pasted

Just opened this because in the PR default comment it asked to create an issue before creating a PR.

In short, it would just be nice to have less typing needed when copying a snippet.

```
def get_monitored_resource_descriptor(
project_id: str, resource_type_name: str
) -> monitored_resource_pb2.MonitoredResourceDescriptor:
"""Prints monitored resource description by type

Args:
project_id: Google Cloud project id
resource_type_name: a monitored resource type

Returns:
An object that describes the monitored resource
"""
# [START monitoring_get_resource]
from google.cloud import monitoring_v3

client = monitoring_v3.MetricServiceClient()
resource_path = (
f"projects/{project_id}/monitoredResourceDescriptors/{resource_type_name}"
)
descriptor = client.get_monitored_resource_descriptor(name=resource_path)
pprint.pprint(descriptor)
# [END monitoring_get_resource]
return descriptor
```

to

```
def get_monitored_resource_descriptor(
project_id: str, resource_type_name: str
) -> monitored_resource_pb2.MonitoredResourceDescriptor:
"""Prints monitored resource description by type

Args:
project_id: Google Cloud project id
resource_type_name: a monitored resource type

Returns:
An object that describes the monitored resource
"""
# [START monitoring_get_resource]
import time
from google.cloud import monitoring_v3

project_id = 'MY_PROJECT_ID'

client = monitoring_v3.MetricServiceClient()
resource_path = (
f"projects/{project_id}/monitoredResourceDescriptors/{resource_type_name}"
)
descriptor = client.get_monitored_resource_descriptor(name=resource_path)
pprint.pprint(descriptor)
# [END monitoring_get_resource]
return descriptor
```

Super minor but wanted to see if anyone else felt the same way.