Make completion resolve async

crates/completion/src/lib.rs

@@ -18,7 +18,10 @@ use crate::{completions::Completions, context::CompletionContext, item::Completi
 
 pub use crate::{
     config::{CompletionConfig, CompletionResolveCapability},
-    item::{CompletionItem, CompletionItemKind, CompletionScore, ImportEdit, InsertTextFormat},
+    item::{
+        CompletionItem, CompletionItemKind, CompletionScore, ImportEdit, ImportEditPtr,
+        InsertTextFormat,
+    },
 };
 
 //FIXME: split the following feature into fine-grained features.