pgsql: Update TODO description for GIT: * Consider smaller indexes that

Log Message:
-----------
Update TODO description for GIT:

* Consider smaller indexes that record a range of values per heap page,
rather than having one index entry for every heap row

Modified Files:
--------------
pgsql/doc:
TODO (r1.2430 -> r1.2431)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/TODO?r1=1.2430&r2=1.2431)
pgsql/doc/src/FAQ:
TODO.html (r1.936 -> r1.937)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/FAQ/TODO.html?r1=1.936&r2=1.937)