Update radiobuttongroup.adoc

Removed unneeded new line breaks.

src/docs/asciidoc/jme3/contributions/tonegodgui/radiobuttongroup.adoc

@@ -13,8 +13,7 @@ ifdef::env-github,env-browser[:outfilesuffix: .adoc]
 *  Manages the interaction between any number of Button derived classes
 *  Provides the abstract method onSelect for executing code when a Radio Button is selected by the user.
 
-+
-*Sample Usage:*+
+*Sample Usage:*
 
 [source,java]
 ----
@@ -43,6 +42,7 @@ rbg.setDisplayElement(null); // null adds the button list to the screen layer
 ----
 
 
+
 === Abstract Event Methods:
 
 [source,java]
@@ -53,6 +53,7 @@ public void onSelect(int index, Button value);
 ----
 
 
+
 === Methods Specific to the CheckBox Class:
 
 [source,java]