Fix EXPLAIN QUERY PLAN so that it describes IN operators implemented using
a ROWID lookup.

FossilOrigin-Name: 60045fbf52162f15f2e18a4e392e80fab19bdbce242728b5e62b0894eac49dfd
diff --git a/src/expr.c b/src/expr.c
index 769d198..112755f 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -2366,7 +2366,8 @@
 
       sqlite3OpenTable(pParse, iTab, iDb, pTab, OP_OpenRead);
       eType = IN_INDEX_ROWID;
-
+      ExplainQueryPlan((pParse, 0,
+            "USING ROWID SEARCH ON TABLE %s FOR IN-OPERATOR",pTab->zName));
       sqlite3VdbeJumpHere(v, iAddr);
     }else{
       Index *pIdx;                         /* Iterator variable */