Use min capture results everywhere

[arora-aman]

Currently, min capture analysis results are written to MaybeTypeckResults, which is a transient data structure within rustc_typeck.

For the results to be available post-typeck they need to be written out to TypeckResults.

The writeback stage in rustc_typeck/src/check/writeback.rs needs to be updated to add the analysis results to the final results table.

[arora-aman]

This will also close rust-lang/rust#76005, since the span will available using tcx.hir().span(capture_info.expr_id)

[arora-aman]

Note once this is implemented we can remove Span from ty::UpvarCapture::ByValue(span) since the capture information contains the expr id corresponding to that span

[arora-aman]

For ease, we can TypeckResults to

1. Add captured_places(closure_def_id: LocalDefId) -> impl Iterator<CapturedPlace<'tcx>> + 'tcx, this returns a the min_captures data structure flattened. (Look flat_map).
2. Remove upvar_capture(), As far as I can see -- this shouldn't be needed since CapturedPlace contains both the CapturInfo and the Place.