pgsql: Remove unnecessary (char *) casts [string]

Remove unnecessary (char *) casts [string]

Remove (char *) casts around string functions where the arguments or
result already have the right type and the cast is useless (or worse,
potentially casts away a qualifier, but this doesn't appear to be the
case here).

Reviewed-by: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
Discussion: https://www.postgresql.org/message-id/flat/fd1fcedb-3492-4fc8-9e3e-74b97f2db6c7%40eisentraut.org

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/506183bce73a2b22308a54876f0a56a249bc26e9

Modified Files
--------------
contrib/fuzzystrmatch/dmetaphone.c          |  8 ++++----
doc/src/sgml/gist.sgml                      |  2 +-
src/backend/replication/walreceiver.c       | 14 +++++++-------
src/backend/replication/walreceiverfuncs.c  |  4 ++--
src/backend/utils/activity/backend_status.c |  6 +++---
src/interfaces/ecpg/pgtypeslib/common.c     |  2 +-
6 files changed, 18 insertions(+), 18 deletions(-)