fix: Fix name resolution when an import is resolved to some namespace and then later in the algorithm another namespace is added
The import is flagged as "indeterminate", and previously it was re-resolved, but only at the end of name resolution, when it's already too late for anything that depends on it.
This issue was tried to fix in https://github.com/rust-lang/rust-analyzer/pull/2466, but it was not fixed fully.
That PR is also why IDE features did work: the import at the end was resolved correctly, so IDE features that re-resolved the macro path resolved it correctly.
I was concerned about the performance of this, but this doesn't seem to regress `analysis-stats .`, so I guess it's fine to land this. I have no idea about the incremental perf however and I don't know how to measure that, although when typing in `zbus` (including creating a new function, which should recompute the def map) completion was fast enough.
I didn't check what rustc does, so maybe it does something more performant, like keeping track of only possibly problematic imports.
Fixes#18138.
Probably fixes#17630.
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