Sorry for changing the subject line.....
these two commits seems not mentioned.Fix ts_headline() edge cases for empty query and empty search text.https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=029dea882a7aa34f46732473eed7c917505e6481
Simplify the implementations of the to_reg* functions.https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=3ea7329c9a79ade27b5d3742d1a41ce6d0d9aca8