[llvm] [GitHub] Allow shortcut for "introductory issue" and request linking to issue in PR (PR #84635)

[Simon Pilgrim via llvm-commits]

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@@ -24,12 +24,12 @@
 
 This issue may be a good introductory issue for people new to working on LLVM. If you would like to work on this issue, your first steps are:
 
-1. In the comments of the issue, request for it to be assigned to you.
+1. In the comments of this issue, request for it to be assigned to you, or just create a [pull request](https://github.com/llvm/llvm-project/pulls) after following the steps below. [Mention](https://docs.github.com/en/issues/tracking-your-work-with-issues/linking-a-pull-request-to-an-issue) this issue in the description of the pull request.
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RKSimon wrote:

As I said earlier, I think assignment should be mandatory. The text should also make it clear that you should communicate with an existing assignee before creating your own PR, give a reasonable amount of time (approx 7 days) for them to respond, and then update the assignment if you agree to take over the ticket.

https://github.com/llvm/llvm-project/pull/84635