fixes#25697
This pull request improves the handling of borrowed routines in the
compiler transformation phase, making the code more robust and
maintainable. The main change is the introduction of a helper function
to properly resolve borrowed routine symbols, which is then used in
multiple places to ensure correct symbol resolution. Additionally, a new
test case is added to cover a previously reported bug related to
borrowed iterators on distinct types.
**Compiler improvements:**
* Added `resolveBorrowedRoutineSym` helper function to follow borrow
aliases and retrieve the underlying implementation symbol for borrowed
routines. This centralizes and clarifies the logic for resolving
borrowed symbols.
* Updated `transformSymAux` and `transformFor` to use the new helper
function, replacing duplicated logic and improving correctness when
handling borrowed routines.
[[1]](diffhunk://#diff-c7b80f51fb685eb22c5b56ee2f320d6c708706f3ae7293478ecd104a2b5b8096L139-R154)
[[2]](diffhunk://#diff-c7b80f51fb685eb22c5b56ee2f320d6c708706f3ae7293478ecd104a2b5b8096L788-R795)
**Testing:**
* Added a test case for bug #25697 to `tests/distinct/tborrow.nim`,
ensuring that iteration over a distinct type with a borrowed iterator
works as expected.
* clean up some test categories
* mention exact slice issue
* magics into system
* move trangechecks into overflow
* move tmemory to system
* try fix CI
* try fix CI
* final CI fix
