Update More block description (#11587)

* Update More block description

* Update packages/block-library/src/more/index.js

Co-Authored-By: Soean <soerenwrede@gmail.com>

packages/block-library/src/more/index.js

@@ -25,7 +25,7 @@ export const name = 'core/more';
 export const settings = {
 	title: _x( 'More', 'block name' ),
 
-	description: __( 'Want to show only an excerpt of this post on your homepage? Use this block to define where you want the separation.' ),
+	description: __( 'Mark the excerpt of this content. Content before this block will be shown in the excerpt on your archives page.' ),
 
 	icon: <SVG viewBox="0 0 24 24" xmlns="http://www.w3.org/2000/svg"><Path fill="none" d="M0 0h24v24H0V0z" /><G><Path d="M2 9v2h19V9H2zm0 6h5v-2H2v2zm7 0h5v-2H9v2zm7 0h5v-2h-5v2z" /></G></SVG>,