app_transfer: Remove LOCAL from documentation.

The Local channel has never supported app_transfer
from what I can see so remove it from the documentation.

ASTERISK-25649

Change-Id: Icbcfe297f6f866285a26b3e9fd5c6d00fa22e0e9

apps/app_transfer.c

@@ -51,7 +51,7 @@
 		</syntax>
 		<description>
 			<para>Requests the remote caller be transferred
-			to a given destination. If TECH (SIP, IAX2, LOCAL etc) is used, only
+			to a given destination. If TECH (SIP, IAX2, etc) is used, only
 			an incoming call with the same channel technology will be transferred.
 			Note that for SIP, if you transfer before call is setup, a 302 redirect
 			SIP message will be returned to the caller.</para>