Rename contrib contains/contained-by operators to @> and <@, per discussion.

contrib/cube/README.cube

contrib/cube/cube.c

contrib/cube/cube.sql.in

contrib/cube/expected/cube.out

contrib/cube/expected/cube_1.out

contrib/cube/expected/cube_2.out

contrib/cube/sql/cube.sql

contrib/cube/uninstall_cube.sql

contrib/earthdistance/README.earthdistance

contrib/earthdistance/expected/earthdistance.out

contrib/earthdistance/sql/earthdistance.sql

contrib/hstore/README.hstore

contrib/hstore/expected/hstore.out

contrib/hstore/hstore.sql.in

contrib/hstore/sql/hstore.sql

contrib/intarray/README.intarray

contrib/intarray/_int.sql.in

contrib/intarray/_int_gin.c

contrib/intarray/_int_gist.c

contrib/intarray/_intbig_gist.c