Restore 'Ss' prefix

Author: topperc

src/naming.adoc

@@ -101,7 +101,7 @@ architecture are prefixed with the letters "Sv", followed by an alphabetical
 name and an optional version number, or by a numeric name with no version number.
 
 Other standard extensions that extend the supervisor-level architecture are 
-named by using ``S'' as a prefix, followed by an alphanumeric name. The name 
+named by using "Ss" as a prefix, followed by an alphanumeric name. The name 
 must end with an alphabetical character or an optional 
 version number. The second letter from the end cannot be numeric character
 if the last letter is ``p''. Supervisor-level extensions must be separated