Only return DefIds to Fn-like definitions in clippy_utils::fn_def_id

[Alexendoo]

Fixes #8850

in returns.rs tcx.fn_sig is called on the result of fn_def_id, which panics if the def is a const/static/etc rather than a functions definition

rust-clippy/clippy_lints/src/returns.rs

Lines 294 to 303 in bc4d39e

	if let Some(def_id) = fn_def_id(self.cx, expr) {
	self.borrows = self
	.cx
	.tcx
	.fn_sig(def_id)
	.output()
	.skip_binder()
	.walk()
	.any(|arg| matches!(arg.unpack(), GenericArgKind::Lifetime(_)));
	}

changelog: Fix ICE due to callable static/consts

[rust-highfive]

r? @llogiq

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[llogiq]

Thank you!

@bors r+

[bors]

📌 Commit 17f7047 has been approved by llogiq

[bors]

⌛ Testing commit 17f7047 with merge 6553b98...

[bors]

☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Approved by: llogiq
Pushing 6553b98 to master...