[misc] Add reminder comment when PR submitted (vllm-project#2092)

### What this PR does / why we need it?
Add reminder comment when PR submitted

### Does this PR introduce _any_ user-facing change?
No

### How was this patch tested?
Test locally:
Yikun#51 (comment)
This PR will take effect after this PR merged.


- vLLM version: v0.10.0
- vLLM main:
vllm-project/vllm@0e36abf

Signed-off-by: Yikun Jiang <[email protected]>

Author: Yikun

.github/workflows/reminder_comment.yml

@@ -0,0 +1,26 @@
+name: PR Reminder Comment Bot
+permissions:
+  pull-requests: write
+on:
+  pull_request_target:
+    types: [opened]
+jobs:
+  pr_reminder:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Remind to run full CI on PR
+        uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # v7.0.1
+        with:
+          script: |
+            github.rest.issues.createComment({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              issue_number: context.issue.number,
+              body: '👋 Hi! Thank you for contributing to the vLLM Ascend project. The following points will speed up your PR merge:‌‌\n\n' +
+                '- A PR should do only one thing, smaller PRs enable faster reviews.\n' +
+                '- Every PR should include unit tests and end-to-end tests ‌to ensure it works and is not broken by other future PRs.\n' +
+                '- Write the commit message by fulfilling the PR description to help reviewer and future developers understand.\n\n' +
+                'If CI fails, you can run linting and testing checks locally according [Contributing](https://vllm-ascend.readthedocs.io/zh-cn/latest/developer_guide/contribution/index.html) and [Testing](https://vllm-ascend.readthedocs.io/zh-cn/latest/developer_guide/contribution/testing.html).'
+            })
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}