Add identify prompt for StarChat.net

Apparently StarChat.net uses a very old (?) or obscure NickServ
service that doesn't send any of the more common prompts for ID.
(It also doesn't support nick grouping, more's the pity.)
(cherry picked from commit e379a7a)

modules/nickserv.cpp

@@ -163,6 +163,7 @@ class CNickServ : public CModule {
 				 || sMessage.find("choose a different nickname") != CString::npos
 				 || sMessage.find("If this is your nick, identify yourself with") != CString::npos
 				 || sMessage.find("If this is your nick, type") != CString::npos
+				 || sMessage.find("This is a registered nickname, please identify") != CString::npos
 				 || sMessage.StripControls_n().find("type /NickServ IDENTIFY password") != CString::npos)
 				&& sMessage.AsUpper().find("IDENTIFY") != CString::npos
 				&& sMessage.find("help") == CString::npos) {