Assert that first letter is capitalized

crates/ra_assists/src/assist_ctx.rs

@@ -84,6 +84,12 @@ impl<'a, DB: HirDatabase> AssistCtx<'a, DB> {
         f: impl FnOnce(&mut AssistBuilder),
     ) -> Option<Assist> {
         let label = AssistLabel { label: label.into(), id };
+        assert_eq!(
+            label.label.chars().nth(0).and_then(|c| Some(c.is_uppercase())),
+            Some(true),
+            "First character should be uppercase"
+        );
+
         let assist = if self.should_compute_edit {
             let action = {
                 let mut edit = AssistBuilder::default();