Auto merge of #89861 - nbdd0121:closure, r=wesleywiser

Closure capture cleanup & refactor

Follow up of #89648

Each commit is self-contained and the rationale/changes are documented in the commit message, so it's advisable to review commit by commit.

The code is significantly cleaner (at least IMO), but that could have some perf implication, so I'd suggest a perf run.

r? `@wesleywiser`
cc `@arora-aman`

clippy_utils/src/lib.rs

@@ -976,8 +976,8 @@ pub fn can_move_expr_to_closure(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) ->
                         };
                         if !self.locals.contains(&local_id) {
                             let capture = match capture.info.capture_kind {
-                                UpvarCapture::ByValue(_) => CaptureKind::Value,
-                                UpvarCapture::ByRef(borrow) => match borrow.kind {
+                                UpvarCapture::ByValue => CaptureKind::Value,
+                                UpvarCapture::ByRef(kind) => match kind {
                                     BorrowKind::ImmBorrow => CaptureKind::Ref(Mutability::Not),
                                     BorrowKind::UniqueImmBorrow | BorrowKind::MutBorrow => {
                                         CaptureKind::Ref(Mutability::Mut)