fix: Build non-ambiguous monikers in crates with multiple targets

[nicolas-guichard]

Previously, a crate which defined multiple targets would cause ambiguous monikers to be built.

For instance when generating an SCIP index in a simple project with a lib and a bin target:

scip-collision/
├── Cargo.toml
└── src/
    ├── lib.rs
    └── main.rs

main.rs:

struct S;

fn main() {}

lib.rs:

struct S;

rust-analyzer scip scip-collision complained with:

Duplicate symbols encountered:

src/lib.rs:0:0-1:0
  Duplicate symbol: rust-analyzer cargo scip-collision 0.1.0 crate/

src/lib.rs:0:7-0:8
  Duplicate symbol: rust-analyzer cargo scip-collision 0.1.0 S#

This fixes the ambiguity by adding the target type and name° to each symbol's moniker. For the example above we now get these symbols:

• rust-analyzer cargo scip-collision 0.1.0 bin/scip_collision/
• rust-analyzer cargo scip-collision 0.1.0 bin/scip_collision/S#
• rust-analyzer cargo scip-collision 0.1.0 bin/scip_collision/main().
• rust-analyzer cargo scip-collision 0.1.0 lib/
• rust-analyzer cargo scip-collision 0.1.0 lib/S#

°: this doesn't add the name for lib, proc-macro and build script targets because there's only one of each per Cargo package

[rustbot]

This PR was rebased onto a different master commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.