Check for try blocks in question_mark more consistently

[y21]

Fixes #12337

I split this PR up into two commits since this moves a method out of an impl, which makes for a pretty bad diff (the &self parameter is now unused, and there isn't a reason for that function to be part of the impl now).

The first commit is the actual relevant change and the 2nd commit just moves stuff (github's "hide whitespace" makes the diff easier to look at)

---

Now for the actual issue:

? within try {} blocks desugars to a break to the block, rather than a return, so that changes behavior in those cases.

The lint has multiple patterns to look for and in some of them it already does correctly check whether we're in a try block, but this isn't done for all of its patterns.

We could add another self.inside_try_block() check to the function that looks for let-else-return, but I chose to actually just move those checks out and instead have them in LintPass::check_{stmt,expr}. This has the advantage that we can't (easily) accidentally forget to add that check in new patterns that might be added in the future.

(There's also a bit of a subtle interaction between two lints, where question_mark's LintPass calls into manual_let_else, so I added a check to make sure we don't avoid linting for something that doesn't have anything to do with ?)

changelog: [question_mark]: avoid linting on try blocks in more cases

[rustbot]

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[bors]

☔ The latest upstream changes (presumably #12348) made this pull request unmergeable. Please resolve the merge conflicts.

[dswij]

Thanks! As always, can you help to solve the conflict here by rebasing? Then it's good to go

[y21]

(Rebased.)

[dswij]

Thank you! @bors r+

[bors]

📌 Commit 1430623 has been approved by dswij

It is now in the queue for this repository.

[bors]

⌛ Testing commit 1430623 with merge e970fa5...

[bors]

☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Approved by: dswij
Pushing e970fa5 to master...