Update duplicate-issues to also post some open PRs for the issues

[bogas04]

I understand that duplicate-issues isn't quite ready yet, however we can update it a bit to be more helpful while its search logic is tweaked.

We can provide links to opened and even merged PRs of the duplicate issue set, this helping both OP & maintainer from looking for them.

@randomdude
Calling Library.someFancyMethod() returns undefined

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@probot
Hi, I'm a bot and I worked hard to find similar issues to the one you posted:

• 1234 someFancyMethod returns undefined
• 4567 someFancyMethod("Hello") returning undefined
• 1337 Undefined returned by someFancyMethod

Please go through them to see if your issue is already listed, in which case you may close this issue.

You can also see the pull requests around these issues, here:

• 136 Add null check for someFancyFunction

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@maintainer
Hi @randomdude, please check 2nd link in above comment. It's the same issue. You can track its development in 136, I think it isn't active anymore, maybe you can take it up?

(I omitted hashes to avoid confusion by referencing random issues).