pgsql: Remove jsonapi.c's lex_accept().

Remove jsonapi.c's lex_accept().

At first glance, this function seems useful, but it actually increases
the amount of code required rather than decreasing it. Inline the
logic into the callers instead; most callers don't use the 'lexeme'
argument for anything and as a result considerable simplification is
possible.

Along the way, fix the header comment for the nearby function
lex_expect(), which mislabeled it as lex_accept().

Patch by me, reviewed by David Steele, Mark Dilger, and Andrew
Dunstan.

Discussion: http://postgr.es/m/CA+TgmoYfOXhd27MUDGioVh6QtpD0C1K-f6ObSA10AWiHBAL5bA@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/530609aa4263bee5b5ca205d83f0dbad098d0465

Modified Files
--------------
src/backend/utils/adt/jsonapi.c | 124 +++++++++++++++++-----------------------
1 file changed, 51 insertions(+), 73 deletions(-)