patch 8.2.2166: auto format doesn't work when deleting text

Problem:    Auto format doesn't work when deleting text.
Solution:   Make "x" trigger auto format. (closes #7504)
diff --git a/src/ops.c b/src/ops.c
index b83394e..743bdd4 100644
--- a/src/ops.c
+++ b/src/ops.c
@@ -938,6 +938,7 @@
 	    curwin->w_cursor = curpos;	// restore curwin->w_cursor
 	    (void)do_join(2, FALSE, FALSE, FALSE, FALSE);
 	}
+	auto_format(FALSE, TRUE);
     }
 
     msgmore(curbuf->b_ml.ml_line_count - old_lcount);