Related issues input should accept an issue ID without the pound sign prefix

Summary

The related issue input box should accept an issue ID regardless if it is prefixed by a # or not:

The placeholder text in the input hints that the # is required, but I still intuitively paste a bare issue ID every time I interact with this control.

In addition, perhaps the placeholder text should read #<issue id> instead of <#issue id> - this would make it a bit more clear that the # is required.