Sync classref with current source

Changes order of brief/long descriptions and removes category
as per godotengine/godot#35132.

classes/class_linkbutton.rst

@@ -11,13 +11,13 @@ LinkButton
 
 **Inherits:** :ref:`BaseButton<class_BaseButton>` **<** :ref:`Control<class_Control>` **<** :ref:`CanvasItem<class_CanvasItem>` **<** :ref:`Node<class_Node>` **<** :ref:`Object<class_Object>`
 
-**Category:** Core
-
-Brief Description
------------------
-
 Simple button used to represent a link to some resource.
 
+Description
+-----------
+
+This kind of button is primarily used when the interaction with the button causes a context change (like linking to a web page).
+
 Properties
 ----------
 
@@ -69,11 +69,6 @@ enum **UnderlineMode**:
 
 - **UNDERLINE_MODE_NEVER** = **2** --- The LinkButton will never show an underline at the bottom of its text.
 
-Description
------------
-
-This kind of button is primarily used when the interaction with the button causes a context change (like linking to a web page).
-
 Property Descriptions
 ---------------------