Set example size for material design icon to 16

Since 16px is an existing default, let's use that in the recommendation
for when using material design icons in the ActionButton.

Signed-off-by: Vincent Petry <vincent@nextcloud.com>

src/components/ActionButton/ActionButton.vue

@@ -49,17 +49,15 @@ You can also use a custom icon, for example from the vue-material-design-icons l
 		<ActionButton>
 			<HandLeft
 				slot="icon"
-				:size="24"
-				fill-color="#000000"
+				:size="16"
 				decorative
 				title="" />
 			Raise left hand
 		</ActionButton>
 		<ActionButton>
 			<HandRight
 				slot="icon"
-				:size="24"
-				fill-color="#000000"
+				:size="16"
 				decorative
 				title="" />
 			Raise right hand