Use new format for all assists that don't change cursor positon

Author: matklad

crates/rust-analyzer/src/to_proto.rs

@@ -639,14 +639,15 @@ fn main() <fold>{
 }
 
 pub(crate) fn code_action(world: &WorldSnapshot, assist: Assist) -> Result<lsp_ext::CodeAction> {
-    let res = if assist.source_change.is_snippet {
+    let res = if assist.source_change.cursor_position.is_none() {
         lsp_ext::CodeAction {
             title: assist.label,
             kind: Some(String::new()),
             edit: Some(snippet_workspace_edit(world, assist.source_change)?),
             command: None,
         }
     } else {
+        assert!(!assist.source_change.is_snippet);
         let source_change = source_change(&world, assist.source_change)?;
         let arg = serde_json::to_value(source_change)?;
         let title = assist.label;