Fix the OP_NullRow documentation so that it accurately describes what it

actually does for a pseudo-cursor.

FossilOrigin-Name: 4e269902094e8f9d852e5fc852e473167048fdeb9034f1fb1436f6df205de926

src/vdbe.c

@@ -5709,6 +5709,10 @@ case OP_Rowid: {                 /* out2 */
 ** Move the cursor P1 to a null row.  Any OP_Column operations
 ** that occur while the cursor is on the null row will always
 ** write a NULL.
+**
+** Or, if P1 is a Pseudo-Cursor (a cursor opened using OP_OpenPseudo)
+** just reset the cache for that cursor.  This causes the row of
+** content held by the pseudo-cursor to be reparsed.
 */
 case OP_NullRow: {
   VdbeCursor *pC;