fix(fenix): use stable toolchain and add wasm32 target

modules/packages.nix

@@ -18,7 +18,18 @@
     direnv
     fh
 
-    fenix.default.toolchain
+    (fenix.combine (
+      with fenix;
+      with stable; [
+        cargo
+        rustc
+        rustfmt
+        clippy
+        rust-src
+        rust-docs
+        targets.wasm32-unknown-unknown.stable.rust-std
+      ]
+    ))
 
     fnm
     deno
@@ -33,7 +44,6 @@
     libffi
     openssl
 
-    rust-analyzer
     nodePackages.typescript-language-server
     dprint