pgsql: Minor clean-up in dshash.{c,h}.

Minor clean-up in dshash.{c,h}.

For consistency with other code that deals in numbers of buckets, the
macro BUCKETS_PER_PARTITION should produce a value of type size_t.
Also, fix a mention of an obsolete proposed name for dshash.c that
appeared in a comment.

Author: Thomas Munro, based on an observation from Amit Kapila
Discussion: https://postgr.es/m/CAA4eK1%2BBOp5aaW3aHEkg5Bptf8Ga_BkBnmA-%3DXcAXShs0yCiYQ%40mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/17b340abf83d1b5f67808c45c63b9e0439569cef

Modified Files
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src/backend/lib/dshash.c | 2 +-
src/include/lib/dshash.h | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)