Improve custom_minimum_size description

doc/classes/Control.xml

@@ -944,7 +944,7 @@
 			Enables whether rendering of [CanvasItem] based children should be clipped to this control's rectangle. If [code]true[/code], parts of a child which would be visibly outside of this control's rectangle will not be rendered and won't receive input.
 		</member>
 		<member name="custom_minimum_size" type="Vector2" setter="set_custom_minimum_size" getter="get_custom_minimum_size" default="Vector2(0, 0)">
-			The minimum size of the node's bounding rectangle. If you set it to a value greater than (0, 0), the node's bounding rectangle will always have at least this size, even if its content is smaller. If it's set to (0, 0), the node sizes automatically to fit its content, be it a texture or child nodes.
+			The minimum size of the node's bounding rectangle. If you set it to a value greater than [code](0, 0)[/code], the node's bounding rectangle will always have at least this size. Note that [Control] nodes have their internal minimum size returned by [method get_minimum_size]. It depends on the control's contents, like text, textures, or style boxes. The actual minimum size is the maximum value of this property and the internal minimum size (see [method get_combined_minimum_size]).
 		</member>
 		<member name="focus_mode" type="int" setter="set_focus_mode" getter="get_focus_mode" enum="Control.FocusMode" default="0">
 			The focus access mode for the control (None, Click or All). Only one Control can be focused at the same time, and it will receive keyboard, gamepad, and mouse signals.