Update documentation to reflect correct limits of memory_page_max

* @config{memory_page_max, the maximum size a page can grow to in

* memory before being reconciled to disk.  The specified size will be

* adjusted to a lower bound of <code>50 * leaf_page_max</code>\, and an

* upper bound of <code>cache_size / 2</code>. This limit is soft - it

* is possible for pages to be temporarily larger than this value.  This

* setting is ignored for LSM trees\, see \c chunk_size., an integer

* between 512B and 10TB; default \c 5MB.}

WT_RET(__wt_config_gets(session, cfg, "memory_page_max", &cval));

btree->maxmempage = (uint64_t)cval.val;

if (!F_ISSET(conn, WT_CONN_CACHE_POOL)) {

	if ((cache_size = conn->cache_size) > 0)

		btree->maxmempage =

		    WT_MIN(btree->maxmempage, cache_size / 10);

}

/* Enforce a lower bound of a single disk leaf page */

btree->maxmempage = WT_MAX(btree->maxmempage, btree->maxleafpage);