docs: update page format to specify page checksum field
Backpatch to 9.3
Per report from Steffen Hildebrandt
Branch
------
master
Details
-------
http://git.postgresql.org/pg/commitdiff/22967d80035427f6e9e31210b7de2e45fafcbc0c
Modified Files
--------------
doc/src/sgml/storage.sgml | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)