docs: about of time -> amount of time (#9052)
docs: about of time -> amount of time (#9052)

typo fix
googleapis/google-cloud-python,tseaver/google-cloud-python,tseaver/google-cloud-python,tswast/google-cloud-python,tseaver/google-cloud-python,googleapis/google-cloud-python,tswast/google-cloud-python,tswast/google-cloud-python,GoogleCloudPlatform/gcloud-python,GoogleCloudPlatform/gcloud-python