fix(rust): Include automatically & set racer path

init/rust-setup.el

@@ -12,3 +12,9 @@
 
 ;; Ensure long compiler errors don't flow out of the screen (very annoying!)
 (add-hook 'cargo-process-mode-hook #'visual-line-mode)
+
+;; I don't use rustup and I'm not sure which derivation would normally place
+;; Rust sources in the nix-store, so I'll continue using my local Rust checkout.
+(setq racer-rust-src-path "~/source/rust")
+
+(provide 'rust-setup)