Update Emoji-cheat-sheet link

[Andre601]

Why:

closes #1992

While I did explain in the above issue why, will I still say the reason here for the sake or documentation.
The doc page explaining emojis links to https://emoji-cheat-sheet.com, while the Guide about GFM and emojis is linking to a repository which seems to be updated.
Since people may get to the docs through the guide would those two different URLs only cause confusion as to which one to look at for up-to-date info.

I now changed the link to point to the aforementioned repository as there is no guarantee (unless GitHub would do this) that the Guide would be updated AND that the emoji-cheat-sheet page only shows emojis supported on GitHub and not also extra ones not available here.

What's being changed:

Section "Using Emojis" of content/github/writing-on-github/basic-writing-and-formatting-syntax.md

Diff:

- For a full list of available emoji and codes, check out [emoji-cheat-sheet.com](http://emoji-cheat-sheet.com).
+ For a full list of available emoji and codes, check out [the Emoji-Cheat-Sheet](https://github.com/ikatyang/emoji-cheat-sheet/blob/master/README.md).

Check off the following:

• All of the tests are passing.
• I have reviewed my changes in staging. (look for the deploy-to-heroku link in your pull request, then click View deployment)
• For content changes, I have reviewed the localization checklist
• For content changes, I have reviewed the Content style guide for GitHub Docs.

[welcome]

Thanks for opening this pull request! A GitHub docs team member should be by to give feedback soon. In the meantime, please check out the contributing guidelines.

[janiceilene]

@Andre601 Thanks so much for opening a PR! I'll get this triaged for review ⚡

[github-actions]

This PR is stale because it has been open 7 days with no activity and will be automatically closed in 3 days. To keep this PR open, update the PR by adding a comment or pushing a commit.

[Andre601]

Is this still being checked?

[janiceilene]

It is! Thanks for your patience! Our small team is working our way through reviewing all of the amazing contributions ✨

[github-actions]

This PR is stale because it has been open 7 days with no activity and will be automatically closed in 3 days. To keep this PR open, update the PR by adding a comment or pushing a commit.

[Andre601]

Yes GitHub Actions, this PR is still active.
Thanks for checking :)

[BxndoBen]

content/github/writing-on-github/basic-writing-and-formatting-syntax.md

[Andre601]

content/github/writing-on-github/basic-writing-and-formatting-syntax.md

I mentioned this before and I mention this again: I and probably anyone else following this PR would appreciate it, if you wouldn't make PR approvals over and over again. While this was just one approval this time was it still not nesessary to do as there were no changes whatsoever that justified it.

[janiceilene]

Thanks for making this change @Andre601 and I'm so sorry it got hit with spammers 💛 I'll update the branch and get this merged once all tests are passing!

[Andre601]

Thanks for making this change @Andre601 and I'm so sorry it got hit with spammers 💛 I'll update the branch and get this merged once all tests are passing!

That's okay as long as those people are dealt with. I reported one user already and also gave the support-team the hint, that they should also check out the other users I mentioned, so hopefully those people will be gone soon enough.

I honestly wish I would understand even half of all the checks/actions made on this PR 😅

[github-actions]

Thanks very much for contributing! Your pull request has been merged 🎉 You should see your changes appear on the site in approximately 24 hours.