chore(deps): move some CLI tools from rtx to cargo install

bat, difftastic and exa don't seem to distribute arm64 binaries as part
of their releases. Hence we need to install them from source with cargo
instead.

zsh/rust.zsh

@@ -79,10 +79,13 @@ install_rust_global_packages() {
       cargo-info
 
     RUSTC_WRAPPER=sccache cargo binstall -y \
-      cargo-update \
-      cargo-edit \
       bacon \
+      bat \
+      cargo-edit \
+      cargo-update \
+      difftastic \
       dirstat-rs \
+      exa \
       hexyl
   )
 }