Remove double spacing after a full stop in help messages.

This hasn't been considered a best practice since the age of the
typewriter.

https://english.stackexchange.com/questions/2544/how-many-spaces-should-come-after-a-period-full-stop

modules/nickserv/ns_resetpass.cpp

@@ -52,7 +52,7 @@ public:
 		source.Reply(" ");
 		source.Reply(_(
 			"Sends a passcode to the nickname with instructions on how to "
-			"reset their password.  Email must be the email address associated "
+			"reset their password. Email must be the email address associated "
 			"to the nickname."
 		));
 		return true;