Update next.md

Author: sylvestre

next.md

@@ -74,3 +74,4 @@ This file documents the pending improvements or regression:
 * https://github.com/uutils/coreutils/pull/8264
 * https://github.com/uutils/coreutils/pull/8296
 * https://github.com/uutils/coreutils/pull/8338
+* https://github.com/uutils/coreutils/pull/8517