Update translation documentation link in pull request template
- [ ] I have made corresponding changes to the documentation
- [ ] I have added tests that prove my fix is effective or that my feature works
- [ ] If I included new strings, I have used `trans.` to make them localizable.
- For more information see our [translations guide](https://napari.org/docs/dev/guides/translations.html).
+ For more information see our [translations guide](https://napari.org/developers/translations.html).
