[COMMITTERS] pgsql: Document BRIN a bit more thoroughly

Document BRIN a bit more thoroughly The chapter "Interfacing Extensions To Indexes" and CREATE OPERATOR CLASS reference page were missed when BRIN was added. We document all our other index access methods there, so make sure BRIN complies. Author: Álvaro Herrera Reported-By: Julien Rouhaud, Tom

[COMMITTERS] pgsql: Document BRIN a bit more thoroughly

Document BRIN a bit more thoroughly The chapter "Interfacing Extensions To Indexes" and CREATE OPERATOR CLASS reference page were missed when BRIN was added. We document all our other index access methods there, so make sure BRIN complies. Author: Álvaro Herrera Reported-By: Julien Rouhaud, Tom