Harmonize more lexer function parameter names.
Make sure that function declarations use names that exactly match the
corresponding names from function definitions for several "lexer
adjacent" backend functions. These were missed by commit
aab06442.
Author: Peter Geoghegan <pg@bowt.ie>
Discussion: https://postgr.es/m/CAH2-WznJt9CMM9KJTMjJh_zbL5hD9oX44qdJ4aqZtjFi-zA3Tg@mail.gmail.com