database/sql: fix subject of unexported func comment

Change-Id: I5db429c86e01b55ec3abc6ab4ca11c221b27f189
Reviewed-on: https://go-review.googlesource.com/c/go/+/177039Reviewed-by: Daniel Theophanes <kardianos@gmail.com>

src/database/sql/convert.go

@@ -98,10 +98,12 @@ func defaultCheckNamedValue(nv *driver.NamedValue) (err error) {
 	return err
 }
 
-// driverArgs converts arguments from callers of Stmt.Exec and
+// driverArgsConnLocked converts arguments from callers of Stmt.Exec and
 // Stmt.Query into driver Values.
 //
 // The statement ds may be nil, if no statement is available.
+//
+// ci must be locked.
 func driverArgsConnLocked(ci driver.Conn, ds *driverStmt, args []interface{}) ([]driver.NamedValue, error) {
 	nvargs := make([]driver.NamedValue, len(args))