Add yamlfmt precommit hook (#2584)

Co-authored-by: Shuchang Zheng <wintonzheng0325@gmail.com>

.github/workflows/publish-fern-docs.yml

@@ -1,10 +1,8 @@
 name: Publish Fern Docs
-
 on:
   push:
     branches:
       - main
-
 jobs:
   run:
     runs-on: ubuntu-latest
@@ -12,12 +10,10 @@ jobs:
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
-
       - name: Install Fern
         run: npm install -g fern-api
-
       - name: Publish Docs
         env:
           FERN_TOKEN: ${{ secrets.FERN_TOKEN }}
           POSTHOG_API_KEY: ${{ secrets.POSTHOG_API_KEY }}
-        run: fern generate --docs 
+        run: fern generate --docs