docs build failed in `google-analytics-admin`

[parthea]

See https://github.com/googleapis/googleapis-gen/blob/e7b50944e6637b70bcedd0bab5d666b2f22ef757/google/analytics/admin/v1alpha/google-analytics-admin-v1alpha-py/google/analytics/admin_v1alpha/services/analytics_admin_service/client.py#L10143 where there is an underscore which is not escaped. If a trailing underscore is not escaped then it is interpreted as a hyperlink.

This caused the docs build to fail with

sphinx.errors.SphinxWarning: /home/runner/work/google-cloud-python/google-cloud-python/packages/google-analytics-admin/google/analytics/admin_v1alpha/services/analytics_admin_service/async_client.py:docstring of google.analytics.admin_v1alpha.services.analytics_admin_service.async_client.AnalyticsAdminServiceAsyncClient.create_calculated_metric:24:Unknown target name: "a-za-z0-9".

Instead of

            calculated_metric_id (str):
                Required. The ID to use for the calculated metric which
                will become the final component of the calculated
                metric's resource name.

                This value should be 1-80 characters and valid
                characters are /[a-zA-Z0-9_]/, no spaces allowed.

It should be

            calculated_metric_id (str):
                Required. The ID to use for the calculated metric which
                will become the final component of the calculated
                metric's resource name.

                This value should be 1-80 characters and valid
                characters are `[a-zA-Z0-9_]`, no spaces allowed.

See https://github.com/googleapis/google-cloud-python/actions/runs/7648352502/job/20840980593?pr=12222

We should add a linter rule to check for trailing underscores in proto comments which are not escaped via https://github.com/googleapis/api-linter .