Complete vec macros with square brackets

crates/ra_ide_api/src/completion/presentation.rs

@@ -108,17 +108,22 @@ impl Completions {
         let ast_node = macro_.source(ctx.db).ast;
         if let Some(name) = name {
             let detail = macro_label(&ast_node);
-            let code_declaration = name + "!";
+
+            let macro_braces_to_insert = match name.as_str() {
+                "vec" => "[$0]",
+                _ => "($0)",
+            };
+            let macro_declaration = name + "!";
 
             let builder = CompletionItem::new(
                 CompletionKind::Reference,
                 ctx.source_range(),
-                &code_declaration,
+                &macro_declaration,
             )
             .kind(CompletionItemKind::Macro)
             .set_documentation(macro_.docs(ctx.db))
             .detail(detail)
-            .insert_snippet(format!("{}($0)", &code_declaration));
+            .insert_snippet(macro_declaration + macro_braces_to_insert);
 
             self.add(builder);
         }