fix(lsp): suggest import map aliases for remaps (#34857)
Summary:
- allow import-map remap diagnostics to suggest meaningful aliases even
when the referrer is inside the mapped directory
- continue skipping passthrough local mappings like `src/` -> `./src/`
- update LSP diagnostics coverage for in-directory alias remaps
Verification:
- `rustfmt --edition 2024 cli/lsp/analysis.rs cli/lsp/diagnostics.rs`
- `git diff --check`
- attempted `cargo test -p deno --lib lsp::diagnostics::tests::test_ --
--nocapture`, but stopped after a long cold compile in the top-level
`deno` test crate; CI should provide the authoritative build/test signal
Refs #13620
Closes denoland/divybot#468
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Co-authored-by: divybot <divybot@users.noreply.github.com>
Co-authored-by: Divy Srivastava <me@littledivy.com>
