Add comment about lsp filtering

Author: MatthewMckee4

crates/ty_ide/src/completion.rs

@@ -4319,6 +4319,8 @@ type <CURSOR>
         assert!(completions.len() == 1);
     }
 
+    /// The following behaviour may not be reflected in editors, since LSP clients may do their own
+    /// filtering of completion suggestions.
     #[test]
     fn from_import_random_name_suggests_import() {
         let builder = completion_test_builder("from typing aa<CURSOR>");