ref-manual: Added note about bb.fatal() raising an exception.

Fixes [YOCTO #10363]

Added a small note to the bullet item about bb.fatal().  Noted
that the function raises an exception so the user does not
have to put a "return" statement after the function call.

(From yocto-docs rev: c27bae87192b7e109d995679c8c91fb3388d8d4c)

Signed-off-by: Scott Rifenbark <srifenbark@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/ref-manual/usingpoky.xml

@@ -902,6 +902,11 @@
                     This logging function is similar to
                     <filename>bb.error(</filename><replaceable>msg</replaceable><filename>)</filename>
                     but also causes the calling task to fail.
+                    <note>
+                        <filename>bb.fatal()</filename> raises an exception,
+                        which means you do not need to put a "return"
+                        statement after the function.
+                    </note>
                     </para></listitem>
             </itemizedlist>
         </para>