3338: new_ret_no_self false positives r=flip1995 a=JoshMcguigan
~~WORK IN PROGRESS~~
I plan to fix all of the false positives in #3313 in this PR, but I wanted to open it now to start gathering feedback.
In this first commit, I've updated the lint to allow tuple return types as long as `Self` shows up at least once, in any position of the tuple. I believe this is the broadest possible interpretation of what should be allowed for tuple return types, but I would certainly be okay making the lint more strict.
fixes#3313
Co-authored-by: Josh Mcguigan <joshmcg88@gmail.com>