stm32 should now work

stm32u5-blinky/.vscode/settings.json

@@ -0,0 +1,9 @@
+{
+    // override the default setting (`cargo check --all-targets`) which produces the following error
+    // "can't find crate for `test`" when the default compilation target is a no_std target
+    // with these changes RA will call `cargo check --bins` on save
+    "rust-analyzer.check.allTargets": false,
+    "rust-analyzer.check.extraArgs": [
+        "--bins"
+    ]
+}