chore: Add notification for no docs changed (#1505)

Author: elliott-with-the-longest-name-on-github

.github/workflows/docs-preview-create.yml

@@ -66,9 +66,11 @@ jobs:
 
       - name: Push
         id: push
+        continue-on-error: true
         run: git add -A && git commit -m "sync docs for repo ${{ inputs.repo }}, pr ${{ inputs.pr }}, commit ${{ inputs.sha }}" && git push -u origin ${{ env.BRANCH }} --force
 
       - name: Request preview comment
+        if: ${{ steps.push.outcome == 'success' }}
         uses: peter-evans/repository-dispatch@v3
         with:
           event-type: 'request-preview-comment'
@@ -77,3 +79,15 @@ jobs:
               "repo": "${{ inputs.repo }}",
               "pr": "${{ inputs.pr }}"
             }
+
+      - name: Dispatch docs-unaffected
+        if: ${{ steps.push.outcome != 'success' }}
+        uses: peter-evans/repository-dispatch@v3
+        with:
+          event-type: 'docs-unaffected'
+          client-payload: |-
+            {
+              "repo": "${{ inputs.repo }}",
+              "pr": "${{ inputs.pr }}",
+              "sha": "${{ inputs.sha }}"
+            }