Use proper assertion in on-type formatting edits

Co-authored-by: DropDemBits <[email protected]>

Author: SomeoneToIgnore

crates/rust-analyzer/src/handlers/request.rs

@@ -354,7 +354,7 @@ pub(crate) fn handle_on_type_formatting(
 
     // This should be a single-file edit
     let (_, (text_edit, snippet_edit)) = edit.source_file_edits.into_iter().next().unwrap();
-    stdx::never!(snippet_edit.is_none(), "on type formatting shouldn't use structured snippets");
+    stdx::always!(snippet_edit.is_none(), "on type formatting shouldn't use structured snippets");
 
     let change = to_proto::snippet_text_edit_vec(&line_index, edit.is_snippet, text_edit);
     Ok(Some(change))