Clarify what makes up the callback function of a use expression

src/content/chapter5_advanced_features/lesson00_use/en.html

@@ -20,8 +20,8 @@
   including zero.
 </p>
 <p>
-  All the following code in the <code class="hljs">{}</code> block becomes the
-  body of the callback function.
+  All the remaining code in the enclosing <code class="hljs">{}</code> block
+  becomes the body of the callback function.
 </p>
 <p>
   This is a very capable and useful feature, but excessive application of