docs(CONTRIBUTING): update links (#977)

* docs(CONTRIBUTING): update links

remove obsolete all-contributors link (was
removed in 1727a49)

* docs: use consistent spelling for TypeScript

... inspired by https://effectivetypescript.com/2021/02/03/pet-peeves/

Co-authored-by: Nick McCurdy <nick@nickmccurdy.com>

Author: leschdom

.github/PULL_REQUEST_TEMPLATE.md

@@ -37,7 +37,7 @@ merge of your pull request!
 - [ ] Documentation added to the
       [docs site](https://github.com/testing-library/testing-library-docs)
 - [ ] Tests
-- [ ] Typescript definitions updated
+- [ ] TypeScript definitions updated
 - [ ] Ready to be merged
       <!-- In your opinion, is this ready to be merged as soon as it's reviewed? -->
 

CONTRIBUTING.md

@@ -8,7 +8,7 @@ series [How to Contribute to an Open Source Project on GitHub][egghead]
 ## Project setup
 
 1.  Fork and clone the repo
-2.  Run `npm run setup` to install dependencies and run validation
+2.  Run `npm run setup -s` to install dependencies and run validation
 3.  Create a branch for your PR with `git checkout -b pr/your-branch-name`
 
 > Tip: Keep your `main` branch pointing at the original repository and make pull
@@ -40,6 +40,5 @@ Also, please watch the repo and respond to questions/bug reports/feature
 requests! Thanks!
 
 [egghead]:
-  https://egghead.io/series/how-to-contribute-to-an-open-source-project-on-github
-[all-contributors]: https://github.com/all-contributors/all-contributors
+  https://egghead.io/courses/how-to-contribute-to-an-open-source-project-on-github
 [issues]: https://github.com/testing-library/dom-testing-library/issues