LSP: Resolve completion items when additional text edits are empty

Rust-analyzer for example sends `Some([])` for completion items and then
sends the actual additional text edits in the completionItem/resolve
response.

helix-term/src/handlers/completion/resolve.rs

@@ -42,9 +42,17 @@ impl ResolveHandler {
         if item.resolved {
             return;
         }
+        // We resolve items when docs or details are missing or when the additional text edits
+        // are either `None` or `Some([])`. The spec is not totally explicit on the conditions
+        // for this and needing to resolve when the additional text edits are `Some([])` is
+        // probably a consequence of how null works in the JavaScript world.
         let needs_resolve = item.item.documentation.is_none()
             || item.item.detail.is_none()
-            || item.item.additional_text_edits.is_none();
+            || !item
+                .item
+                .additional_text_edits
+                .as_ref()
+                .is_some_and(|edits| !edits.is_empty());
         if !needs_resolve {
             item.resolved = true;
             return;