chan_sip: Clarify that sipdebug=yes cannot be undone by the CLI.

Document it in sip.conf.

ASTERISK-24249 #close
Reported by: Avinash Mohod

Review: https://reviewboard.asterisk.org/r/3926/
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Merged revisions 423066 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 423067 from http://svn.asterisk.org/svn/asterisk/branches/11
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Merged revisions 423068 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/13@423069 65c4cc65-6c06-0410-ace0-fbb531ad65f3

configs/samples/sip.conf.sample

@@ -651,7 +651,9 @@ srvlookup=yes                   ; Enable DNS SRV lookups on outbound calls
 ;
 ;--------------------------- SIP DEBUGGING ---------------------------------------------------
 ;sipdebug = yes                 ; Turn on SIP debugging by default, from
-                                ; the moment the channel loads this configuration
+                                ; the moment the channel loads this configuration.
+                                ; NOTE: You cannot use the CLI to turn it off. You'll
+                                ; need to edit this and reload the config.
 ;recordhistory=yes              ; Record SIP history by default
                                 ; (see sip history / sip no history)
 ;dumphistory=yes                ; Dump SIP history at end of SIP dialogue