Fix code example (#11487)

Fix example of using grid.setStyleGenerator in one line

documentation/components/components-grid.asciidoc

 
 [source, java]
 ----
-grid.setStyleGenerator(person -> {
+grid.setStyleGenerator(person ->
     // Style based on alive status
-    person.isAlive() ? null : "dead";
-});
+    person.isAlive() ? null : "dead"
+);
 ----
 
 You could then style the rows with CSS as follows: