pgsql: Fix some typos and inconsistencies in tableam.h

Fix some typos and inconsistencies in tableam.h

The defined callback definitions have been using references to heap for
a couple of variables and comments. This makes the whole interface more
consistent by using "table" which is more generic.

A variable storing index information was misspelled as well.

Author: Michael Paquier
Discussion: https://postgr.es/m/20190601190946.GB1905@paquier.xyz

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/041a2642e51eb008351435709dcb054760a43bb9

Modified Files
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src/include/access/tableam.h | 90 ++++++++++++++++++++++----------------------
1 file changed, 45 insertions(+), 45 deletions(-)