pgsql: Add pg_nodiscard decorations to base64 functions

Add pg_nodiscard decorations to base64 functions

The result of pg_b64_encode() and pg_b64_decode() should be checked
for errors. This attribute could detect mistakes such as those fixed
in commit ff030ebe250 and d278541be42.

Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Ranier Vilela <ranier.vf@gmail.com>
Discussion: /messages/by-id/CAEudQAq-3yHsSdWoOOaw+gAQYgPMpMGuB5pt2yCXgv-YuxG2Hg@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/b0eff1098860f88dd385e6882ff7b1063d267213

Modified Files
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src/include/common/base64.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)