Mention how /nickserv is a common but not universal alias

Closes GH-82.

use/identifying_to_services.rst

@@ -18,7 +18,7 @@ services.
 
 First start by checking what is the syntax for registering with
 ``/msg nickserv help register``. It returns you something like this (Atheme
-7.2.4)::
+7.x)::
 
     NickServ: Syntax: REGISTER <password> <email-address>
 
@@ -35,9 +35,15 @@ it does, go to the email address and run::
 Now your bot should be successfully registered and you can move to setting
 up automatic identifying below. If you need to identify to services now,
 ``/msg nickserv help identify`` and following the syntax (I am still
-assuming that you are on Atheme 7.2.4)
+assuming that you are on Atheme 7.x)
 ``owner ircquote nickserv identify username password``.
 
+Note: on *most* networks, ``/nickserv`` is defined as a server-side alias which
+forwards text to NickServ; this is why ``ircquote nickserv`` often will work
+out of the box. On networks where this is not the case, you may need to run
+something like ``ircquote privmsg nickserv :register ...`` instead (notice
+the placement of the ``:`` after ``nickserv`` and before the command name).
+
 SASL PLAIN
 ----------