fix: goto-definition for constants inside range pattern 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.