Rollup merge of #90349 - willcrichton:example-analyzer, r=jyn514

Rollup merge of #90349 - willcrichton:example-analyzer, r=jyn514

Fix rare ICE during typeck in rustdoc scrape_examples

While testing the `--scrape-examples` extension on the [wasmtime](https://github.com/bytecodealliance/wasmtime) repository, I found some additional edge cases. Specifically, when asking to typecheck a body containing a function call, I would sometimes get an ICE if:
* The body doesn't exist
* The function's HIR node didn't have a type

This adds checks for both of those conditions.

(Also this updates a test to check that the sources of a reverse-dependency are correctly generated and linked.)

r? `@jyn514`