correct spelling of 'details' in pr template
**Note**: _that new categories can be added only when there are 3 packages or more._
**Make sure that you've checked the boxes below that apply before you submit PR.**
-_Not every repository (project) will require every option, but most projects should. Check the Contribution Guidelines for detials._
+_Not every repository (project) will require every option, but most projects should. Check the Contribution Guidelines for details._
- [ ] The package has been added to the list in alphabetical order.
- [ ] The package has an appropriate description with correct grammar.
