docs: update proto comments

[yoshi-automation]

This PR was generated using Autosynth. 🌈

Here's the log from Synthtool:

synthtool > Cloning googleapis.
synthtool > Running generator for google/monitoring/artman_monitoring.yaml.
synthtool > Ensuring dependencies.
synthtool > Pulling artman image.
latest: Pulling from googleapis/artman
Digest: sha256:229601142daed005bf56fbaa21a02cf7aa0b261b57677d38306f8013e536de7a
Status: Image is up to date for googleapis/artman:latest
synthtool > Generated code into /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/js/monitoring-v3.
.circleci/config.yml
.circleci/npm-install-retry.js
.eslintignore
.eslintrc.yml
.github/CONTRIBUTING.md
.github/ISSUE_TEMPLATE/bug_report.md
.github/ISSUE_TEMPLATE/feature_request.md
.github/ISSUE_TEMPLATE/support_request.md
.jsdoc.js
.kokoro/common.cfg
.kokoro/continuous/node10/common.cfg
.kokoro/continuous/node10/test.cfg
.kokoro/continuous/node11/common.cfg
.kokoro/continuous/node11/test.cfg
.kokoro/continuous/node6/common.cfg
.kokoro/continuous/node6/test.cfg
.kokoro/continuous/node8/common.cfg
.kokoro/continuous/node8/docs.cfg
.kokoro/continuous/node8/lint.cfg
.kokoro/continuous/node8/samples-test.cfg
.kokoro/continuous/node8/system-test.cfg
.kokoro/continuous/node8/test.cfg
.kokoro/docs.sh
.kokoro/lint.sh
.kokoro/presubmit/node10/common.cfg
.kokoro/presubmit/node10/test.cfg
.kokoro/presubmit/node11/common.cfg
.kokoro/presubmit/node11/test.cfg
.kokoro/presubmit/node6/common.cfg
.kokoro/presubmit/node6/test.cfg
.kokoro/presubmit/node8/common.cfg
.kokoro/presubmit/node8/docs.cfg
.kokoro/presubmit/node8/lint.cfg
.kokoro/presubmit/node8/samples-test.cfg
.kokoro/presubmit/node8/system-test.cfg
.kokoro/presubmit/node8/test.cfg
.kokoro/presubmit/windows/common.cfg
.kokoro/presubmit/windows/test.cfg
.kokoro/samples-test.sh
.kokoro/system-test.sh
.kokoro/test.bat
.kokoro/test.sh
.kokoro/trampoline.sh
.nycrc
CODE_OF_CONDUCT.md
codecov.yaml
npm WARN deprecated [email protected]: CircularJSON is in maintenance only, flatted is its successor.
npm WARN deprecated [email protected]: no longer maintained

> [email protected] install /tmpfs/src/git/autosynth/working_repo/node_modules/grpc
> node-pre-gyp install --fallback-to-build --library=static_library

node-pre-gyp WARN Using request for node-pre-gyp https download 
[grpc] Success: "/tmpfs/src/git/autosynth/working_repo/node_modules/grpc/src/node/extension_binary/node-v57-linux-x64-glibc/grpc_node.node" is installed via remote

> [email protected] postinstall /tmpfs/src/git/autosynth/working_repo/node_modules/protobufjs
> node scripts/postinstall

npm notice created a lockfile as package-lock.json. You should commit this file.
npm WARN [email protected] requires a peer of acorn@^6.0.0 but none is installed. You must install peer dependencies yourself.
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: [email protected] (node_modules/fsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for [email protected]: wanted {"os":"darwin","arch":"any"} (current: {"os":"linux","arch":"x64"})

added 1153 packages from 1283 contributors and audited 6352 packages in 20.672s
found 0 vulnerabilities


> @google-cloud/[email protected] fix /tmpfs/src/git/autosynth/working_repo
> eslint '**/*.js' --fix


/tmpfs/src/git/autosynth/working_repo/samples/alerts.js
   30:30  error  "@google-cloud/monitoring" is not found  node/no-missing-require
   71:30  error  "@google-cloud/monitoring" is not found  node/no-missing-require
  136:30  error  "@google-cloud/monitoring" is not found  node/no-missing-require
  180:30  error  "@google-cloud/monitoring" is not found  node/no-missing-require
  235:30  error  "@google-cloud/monitoring" is not found  node/no-missing-require

/tmpfs/src/git/autosynth/working_repo/samples/metrics.js
   29:30  error  "@google-cloud/monitoring" is not found  node/no-missing-require
   87:30  error  "@google-cloud/monitoring" is not found  node/no-missing-require
  119:30  error  "@google-cloud/monitoring" is not found  node/no-missing-require
  162:30  error  "@google-cloud/monitoring" is not found  node/no-missing-require
  192:30  error  "@google-cloud/monitoring" is not found  node/no-missing-require
  249:30  error  "@google-cloud/monitoring" is not found  node/no-missing-require
  296:30  error  "@google-cloud/monitoring" is not found  node/no-missing-require
  343:30  error  "@google-cloud/monitoring" is not found  node/no-missing-require
  396:30  error  "@google-cloud/monitoring" is not found  node/no-missing-require
  451:30  error  "@google-cloud/monitoring" is not found  node/no-missing-require
  495:30  error  "@google-cloud/monitoring" is not found  node/no-missing-require

/tmpfs/src/git/autosynth/working_repo/samples/quickstart.js
  20:28  error  "@google-cloud/monitoring" is not found  node/no-missing-require

/tmpfs/src/git/autosynth/working_repo/samples/system-test/alerts.test.js
  19:28  error  "@google-cloud/monitoring" is not found  node/no-missing-require

/tmpfs/src/git/autosynth/working_repo/samples/system-test/metrics.test.js
  18:28  error  "@google-cloud/monitoring" is not found  node/no-missing-require

/tmpfs/src/git/autosynth/working_repo/samples/uptime.js
   29:30  error  "@google-cloud/monitoring" is not found  node/no-missing-require
   89:30  error  "@google-cloud/monitoring" is not found  node/no-missing-require
  139:30  error  "@google-cloud/monitoring" is not found  node/no-missing-require
  166:30  error  "@google-cloud/monitoring" is not found  node/no-missing-require
  216:30  error  "@google-cloud/monitoring" is not found  node/no-missing-require
  254:30  error  "@google-cloud/monitoring" is not found  node/no-missing-require

✖ 25 problems (25 errors, 0 warnings)

npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! @google-cloud/[email protected] fix: `eslint '**/*.js' --fix`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the @google-cloud/[email protected] fix script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/kbuilder/.npm/_logs/2018-11-11T12_15_48_385Z-debug.log
synthtool > Cleaned up 2 temporary directories.