Fix wrong comments.

Author: junaruga

.github/workflows/build.yml

@@ -32,10 +32,10 @@ jobs:
           - {os: ubuntu-16.04, ruby: 2.4, db: mariadb10.0, allow-failure: true}
           # Comment out due to ci/setup.sh stucking.
           # - {os: ubuntu-18.04, ruby: 2.4, db: mariadb10.1, allow-failure: false}
-          # Allow failure due to the issue #1165.
+          # `service mysql restart` fails.
           - {os: ubuntu-20.04, ruby: 2.4, db: mariadb10.3, allow-failure: true}
           - {os: ubuntu-18.04, ruby: 2.4, db: mysql57, allow-failure: false}
-          # `service mysql restart` fails.
+          # Allow failure due to the issue #1165.
           - {os: ubuntu-20.04, ruby: 2.4, db: mysql80, allow-failure: true}
           - {os: ubuntu-18.04, ruby: 'head', db: '', allow-failure: true}
           # db: A DB's brew package name in macOS case.