Multilang: Instructions to preview alerts (#28718)

* Multilang: Instructions to preview alerts

* move instructions to separete section

* Update README.md

* <br>

* move up

* Update README.md

* Update README.md

* Update README.md

* Update README.md

* Update README.md

* a step

---------

Co-authored-by: Shane Smiskol <shane@smiskol.com>

selfdrive/ui/translations/README.md

@@ -31,11 +31,22 @@ openpilot provides a few tools to help contributors manage their translations an
    ```shell
    scons -j$(nproc) selfdrive/ui && selfdrive/ui/ui
    ```
+5. Read [Checking the UI](#checking-the-ui) to double-check your translations fit in the UI.
 
 ### Improving an Existing Language
 
 Follow step 3. above, you can review existing translations and add missing ones. Once you're done, just open a pull request to openpilot.
 
+### Checking the UI
+Different languages use varying space to convey the same message, so it's a good idea to double-check that your translations do not overlap and fit into each widget. Start the UI (step 4. above) and view each page, making adjustments to translations as needed.
+
+#### To view offroad alerts:
+
+With the UI started, you can view the offroad alerts with:
+```shell
+selfdrive/ui/tests/cycle_offroad_alerts.py
+```
+
 ### Updating the UI
 
 Any time you edit source code in the UI, you need to update the translations to ensure the line numbers and contexts are up to date (first step above).