pgsql: doc: Fix a couple of mistakes in pgplanadvice.sgml

doc: Fix a couple of mistakes in pgplanadvice.sgml

It said FOREIGN_SCAN where it should say FOREIGN_JOIN.

NESTED_LOOP_MEMOIZE was mistakenly omitted from the list of join
methods.

Author: Lakshmi N <lakshmin.jhs@gmail.com>
Reviewed-by: jie wang <jugierwang@gmail.com>
Discussion: http://postgr.es/m/CA+3i_M-mo7Of=Pn8WzRfJLt=fc=gDTn1oOdj8v8BEtgXh9ZMCg@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/f4a4f1a7e6285c846a4c2662d8ce5246a6bcb7e7

Modified Files
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doc/src/sgml/pgplanadvice.sgml | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)