message: fix(docs-infra): log the successful creation of previews
  This can help with debugging issues, e.g. with the communication between
  the preview server and CI, as it gives a better idea of exactly when was
  the preview made available and how long it took.
  PR Close
diff: @@ -7,7 +7,7 @@ import {CircleCiApi} from '../common/circle-ci-api';
  import {GithubApi} from '../common/github-api';
  import {GithubPullRequests} from '../common/github-pull-requests';
  import {GithubTeams} from '../common/github-teams';
  -import {assert, assertNotMissingOrEmpty, Logger} from '../common/utils';
  +import {assert, assertNotMissingOrEmpty, computeShortSha, Logger} from '../common/utils';
  import {BuildCreator} from './build-creator';
  import {ChangedPrVisibilityEvent, CreatedBuildEvent} from './build-events';
  import {BuildRetriever} from './build-retriever';
  @@ -144,7 +144,10 @@ export class PreviewServerFactory {
  const artifactPath = await buildRetriever.downloadBuildArtifact(buildNum, pr, sha, cfg.buildArtifactPath);
  const isPublic = await buildVerifier.getPrIsTrusted(pr);
  await buildCreator.create(pr, sha, artifactPath, isPublic);
  +
  res.sendStatus(isPublic ? 201 : 202);
  + logger.log(`PR:${pr}, SHA:${computeShortSha(sha)}, Build:${buildNum} - ` +
  + `Successfully created ${isPublic ? 'public' : 'non-public'} preview.`);
  } catch (err) {
  logger.error('CircleCI webhook error', err);
  respondWithError(res, err);
  