radv: update internal reference

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4630>
diff --git a/src/amd/vulkan/radv_debug.h b/src/amd/vulkan/radv_debug.h
index 979b448..6360503 100644
--- a/src/amd/vulkan/radv_debug.h
+++ b/src/amd/vulkan/radv_debug.h
@@ -26,7 +26,7 @@
 
 #include "radv_private.h"
 
-/* Please keep docs/envvars.html up-to-date when you add/remove options. */
+/* Please keep docs/envvars.rst up-to-date when you add/remove options. */
 enum {
 	RADV_DEBUG_NO_FAST_CLEARS    =   0x1,
 	RADV_DEBUG_NO_DCC            =   0x2,