[skip ci] Add symbol to label content (#8842)

Signed-off-by: Nshiyu22 <shiyu.chen@zilliz.com>

CODE_REVIEW.md

@@ -3,9 +3,9 @@
 All PRs are checked in automatically by the sre-robot, with the following condition:
 
 1. DCO check passed
-2. All test passed and code coverage check passed, with a "ci-passed" label
-4. Reviewe passed, with a "lgtm" label
-5. Approver passed, with a "approved" label
+2. All test passed and code coverage check passed, with a `ci-passed` label
+4. Reviewe passed, with a `lgtm` label
+5. Approver passed, with a `approved` label
 
 Generally speaking, reviewer is volunteered and can be anyone in the community who is familiar with the packages the PR modifies.
 Reviewers are responsible for the logic correctness, error handling, unit test coverage and code readability.