send-email: document --no-[to|cc|bcc]

These options added in f434c08 ("send-email: add --no-cc, --no-to,
and --no-bcc", 2010-03-07) were never documented.

Signed-off-by: Ævar Arnfjörð Bjarmason <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: avar

Documentation/git-send-email.txt

@@ -273,6 +273,10 @@ must be used for each option.
 Automating
 ~~~~~~~~~~
 
+--no-[to|cc|bcc]::
+	Clears any list of "To:", "Cc:", "Bcc:" addresses previously
+	set via config.
+
 --to-cmd=<command>::
 	Specify a command to execute once per patch file which
 	should generate patch file specific "To:" entries.