Add `rustc` libraries to `rust-analyzer`

[sandydoo]

Adds the rustc libraries to the runtime path of rust-analyzer.

Tested on:

➜ uname -a
Linux nixos 6.8.4 #1-NixOS SMP Thu Apr  4 18:25:06 UTC 2024 aarch64 GNU/Linux

Repro

nix shell -f . stable.rust-analyzer
rust-analyzer --version

Expected

rust-analyzer 1.77.2 (25ef9e3d 2024-04-09)

Actual

rust-analyzer: error while loading shared libraries: librustc_driver-4766cc27bbc2a07e.so: cannot open shared object file: No such file or directory

[domenkozar]

cc @figsoda