docs: fix spelling error in design docs (pingcap#8893)

docs/design/README.md

@@ -9,7 +9,7 @@ Writing a design document can promote us to think deliberately and gather knowle
 ## Proprosal Process
 
 1. Before starting to write a design document, please [create a new issue](https://github.com/pingcap/tidb/issues/new/choose) for tracing the process of your design.
-2. Create a new [Google Doc](https://docs.google.com/document/u/0/) to write the design document. Pelase refer to this [proposal template](./TEMPLATE.md).
+2. Create a new [Google Doc](https://docs.google.com/document/u/0/) to write the design document. Please refer to this [proposal template](./TEMPLATE.md).
 3. If the design document is ready to be reviewed, please put the shared link with the `can comment` permission in the issue you've created, and one of our engineers will follow up this issue and keep it updated.
 4. If needed, we may organize a communications seminar through [Google Hangouts](https://hangouts.google.com/) to discuss your design with you and the interested friends from the community.
 5. When your design is finalized, please submit a pull request (PR) to add your new file under this directory, and put the link of your PR in the issue you've created.