Added go links to clarify common questions (GoogleCloudPlatform#13273)

Author: melinath

.ci/magician/cmd/templates/DIFF_COMMENT.md.tmpl

@@ -47,7 +47,7 @@ The following new resources do not have corresponding service labels:
 {{- range .MissingServiceLabels}}
 - {{.}}{{end}}
 
-If you believe this detection to be incorrect please raise the concern with your reviewer.
+If you believe this detection to be incorrect please raise the concern with your reviewer. Googlers: This error is safe to ignore once you've completed go/fix-missing-service-labels.
 An `override-missing-service-label` label can be added to allow merging.
 {{end}}
 

.ci/magician/github/REVIEWER_ASSIGNMENT_COMMENT.md

@@ -1,4 +1,4 @@
-Hello! I am a robot. Tests will require approval from a repository maintainer to run.
+Hello! I am a robot. Tests will require approval from a repository maintainer to run. Googlers: see go/terraform-auto-test-runs to set up automatic test runs.
 
 @{{.reviewer}}, a repository maintainer, has been assigned to [review your changes](https://googlecloudplatform.github.io/magic-modules/contribute/review-pr/). If you have not received review feedback within 2 business days, please leave a comment on this PR asking them to take a look.