fix(editor): add placeholder for input of database context menu (#11079)

fix: BS-2594

blocksuite/affine/blocks/block-database/src/database-block.ts

@@ -109,7 +109,7 @@ export class DatabaseBlockComponent extends CaptionedBlockComponent<DatabaseBloc
       items: [
         menu.input({
           initialValue: this.model.props.title.toString(),
-          placeholder: 'Untitled',
+          placeholder: 'Database title',
           onChange: text => {
             this.model.props.title.replace(
               0,