Add infrastructure to narrow down diagnostic ranges

[matklad]

In #10499 and #10425 I've implemented some hacks to narrow down diagnostics range. "Remove this semicolon" diagnostics points to the whole expr_stmt, while we want to highlight only the ;. Similarly, for mismatch arg count we want to highlight only extra/missing args.

The impl there works for the common cases, but is wrong in general.

The overall problem is that diagnostic point to a syntax node in a potentially macro expanded file. We want to narrow this range down while still in the macro-expanded file, but then map it to the original file.

diagnostics_display_range doesn't support this API. We probably should remove diagnostics_display_range from Semancis entirely, and instead implement a helper for that in ide_diagnostics directly, such that it supports sub-node ranges.