fix: goto-definition for constants inside range pattern

[roife]

Fix #15653.

This PR addresses the issue where it was not possible to navigate to constants in range patterns, specifically including two major changes:

1. Previously, both the start and end fields in Pat::Range were of type LiteralOrConst. When performing goto-definition on constants inside range patterns, r-a would use resolve_bind_pat_to_const to find their definitions. However, because the content of a Const is not Pat but Path, it was not stored in the source_map, so resolve_bind_pat_to_const would returns None. This PR changes them to Const(PatId), so that during the lowering process, they are considered as a pat, allowing their definitions to be found later through resolve_bind_pat_to_const.

2. The process related to range patterns in MIR-lowering has been modified to correctly handle the above changes.

[Veykril]

Thanks
@bors r+

[bors]

📌 Commit 9cc3a9c has been approved by Veykril

It is now in the queue for this repository.

[bors]

⌛ Testing commit 9cc3a9c with merge 223238d...

[bors]

☀️ Test successful - checks-actions
Approved by: Veykril
Pushing 223238d to master...