If the user provides likelihood() data for a WHERE clause term used as part of an index key, have the planner use it when calculating the expected number of rows visited by the loop.

FossilOrigin-Name: c51efaa5d29ee0a91b9e6a83a8dd82530670811a

src/whereInt.h

@@ -458,3 +458,4 @@ struct WhereInfo {
 #define WHERE_AUTO_INDEX   0x00004000  /* Uses an ephemeral index */
 #define WHERE_SKIPSCAN     0x00008000  /* Uses the skip-scan algorithm */
 #define WHERE_UNQ_WANTED   0x00010000  /* WHERE_ONEROW would have been helpful*/
+#define WHERE_LIKELIHOOD   0x00020000  /* A likelihood() is affecting nOut */