Apply suggestions from code review

Co-authored-by: Lia Corrales <lia.astro@gmail.com>
Co-authored-by: Kelle Cruz <kellecruz@gmail.com>

Author: 3 people

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,6 +1,7 @@
-- [ ] Please check out our [contributing
+- [ ] Check the box to confirm that you are familiar with the [contributing
   guidelines](https://learn.astropy.org/contributing/how-to-contribute) and/or
   indicate (check the box) that you are familiar with our contributing workflow.
-- [ ] Please also be sure to check out our [code of
+  - [ ] The tutorial contains a complete Introduction which includes an Author list, Learning Goals, Keywords, Companion Content (if applicable), and a Summary.
+- [ ] Check the box to confirm that you are familiar with the Astropy community [code of
   conduct](https://github.com/astropy/astropy/blob/main/CODE_OF_CONDUCT.md) and
   check this box to agree to follow the CoC.