[master] 53958d63d vrt.h: Mention new VRT_r_obj_stale_is_valid()

[Walid Boudebouda]

commit 53958d63d2352d1af6473a6a1756cba87364ece2
Author: Walid Boudebouda <walid.boudebouda at gmail.com>
Date:   Mon Sep 15 12:00:24 2025 +0200

    vrt.h: Mention new VRT_r_obj_stale_is_valid()

diff --git a/include/vrt.h b/include/vrt.h
index 188ab693e..c854b88f3 100644
--- a/include/vrt.h
+++ b/include/vrt.h
@@ -70,6 +70,7 @@
  *	VRT_r_obj_stale_time() added
  *	VRT_r_obj_stale_ttl() added
  *	VRT_r_obj_stale_uncacheable() added
+ *	VRT_r_obj_stale_is_valid() added
  *	enum gethdr_e has new value HDR_OBJ_STALE
  *	typedef hdr_t added
  *	struct gethdr_s.what changed to hdr_t