Merge #574

574: refactor completions to use TextEdit instead of InsertText r=matklad a=gfreezy

1. migrate from `insertText` to `TextEdit` from `CompleteItem`
2. use `insta` to test completions

Co-authored-by: gfreezy <gfreezy@gmail.com>

crates/ra_ide_api/src/lib.rs

@@ -43,7 +43,7 @@ use crate::{
 };
 
 pub use crate::{
-    completion::{CompletionItem, CompletionItemKind, InsertText},
+    completion::{CompletionItem, CompletionItemKind, InsertTextFormat},
     runnables::{Runnable, RunnableKind},
     navigation_target::NavigationTarget,
 };