Prettier comment (#6928)

Just making our CI workflow print a message with a suggestion for how to
fix linter issues.

See text on previous CI run, before actually fixing the issues I
introduced:
https://github.com/tensorflow/tensorboard/actions/runs/11376055312/job/31647872238

.github/workflows/ci.yml

@@ -316,8 +316,9 @@ jobs:
         with:
           node-version: 16
       - run: yarn install --ignore-engines
-        # You can run `yarn fix-lint` to fix all Prettier complaints.
-      - run: yarn lint
+        # You can run `yarn fix-lint` to fix all Prettier complaints, although at this point this will try to fix too many things.
+        # To fix only the files changed in this PR, see the command below.
+      - run: yarn lint || (( echo 'Try running `$ prettier --write $(git diff-tree --no-commit-id --name-only <latest commit> <parent branch commit> -r)`.' && false ))
         # Make sure no tests are skipped with "focused" tests.
       - run: |
           ! git grep -E 'f(it|describe)\(' 'tensorboard/*_test.ts'