Update contributing doc and PR template for examples (#37193)

* Update contributing doc and PR template for examples

* Apply suggestions from code review

Co-authored-by: Steven <steven@ceriously.com>

.github/pull_request_template.md

@@ -22,3 +22,4 @@ Choose the right checklist for the change that you're making:
 ## Documentation / Examples
 
 - [ ] Make sure the linting passes by running `yarn lint`
+- [ ] The examples guidelines are followed from [our contributing doc](https://github.com/vercel/next.js/blob/canary/contributing.md#adding-examples)

contributing.md

@@ -265,7 +265,15 @@ Below are the steps to add a new link:
 
 ## Adding examples
 
-When you add an example to the [examples](examples) directory, don’t forget to add a `README.md` file with the following format:
+When you add an example to the [examples](examples) directory, please follow these guidelines to ensure high quality examples:
+
+- TypeScript should be leveraged for new examples (no need for separate JavaScript and TypeScript examples)
+- Examples should not add custom eslint configuration (we have specific templates for eslint)
+- If API routes aren't used in an example, they should be omitted
+- If an example exists for a certain library and you would like to showcase a specific feature of that library, the existing example should be updated (instead of adding a new example)
+- Package manager specific config should not be added (e.g. `resolutions` in `package.json`)
+
+Also don’t forget to add a `README.md` file with the following format:
 
 - Replace `DIRECTORY_NAME` with the directory name you’re adding.
 - Fill in `Example Name` and `Description`.