Button: Repeat limitation for button content in label option's desc

Fixes #282
Closes #284

Author: jzaefferer

entries/button.xml

@@ -45,11 +45,15 @@
 				<p>Icons to display, with or without text (see <a href="#option-text"><code>text</code></a> option). By default, the primary icon is displayed on the left of the label text and the secondary is displayed on the right. The positioning can be controlled via CSS.</p>
 
 				<p>The value for the <code>primary</code> and <code>secondary</code> properties must match <a href="/theming/icons/">an icon class name</a>, e.g., <code>"ui-icon-gear"</code>. For using only one icon: <code>icons: { primary: "ui-icon-locked" }</code>. For using two icons: <code>icons: { primary: "ui-icon-gear", secondary: "ui-icon-triangle-1-s" }</code>.</p>
+				<p>When using an input of type button, submit or reset, icons are not supported.</p>
 			</desc>
 			<type name="Object" />
 		</option>
 		<option name="label" default="null" example-value='"custom label"'>
-			<desc>Text to show in the button. When not specified (<code>null</code>), the element's HTML content is used, or its <code>value</code> attribute if the element is an input element of type submit or reset, or the HTML content of the associated label element if the element is an input of type radio or checkbox.</desc>
+			<desc>
+				<p>Text to show in the button. When not specified (<code>null</code>), the element's HTML content is used, or its <code>value</code> attribute if the element is an input element of type submit or reset, or the HTML content of the associated label element if the element is an input of type radio or checkbox.</p>
+				<p>When using an input of type button, submit or reset, support is limited to plain text labels.</p>
+			</desc>
 			<type name="String" />
 		</option>
 		<option name="text" default="true" example-value="false">