[master] 5e2804f26 release docs: req.grace/req.ttl wording

[Nils Goroll]

commit 5e2804f26402fa901bc13825bd5fcdc98a235796
Author: Nils Goroll <nils.goroll at uplex.de>
Date:   Mon Sep 10 19:36:08 2018 +0200

    release docs: req.grace/req.ttl wording

diff --git a/doc/sphinx/whats-new/upgrading-6.1.rst b/doc/sphinx/whats-new/upgrading-6.1.rst
index 997746f12..df71404f1 100644
--- a/doc/sphinx/whats-new/upgrading-6.1.rst
+++ b/doc/sphinx/whats-new/upgrading-6.1.rst
@@ -56,15 +56,15 @@ VCL variables
 ``req.ttl``, ``req.grace`` and keep
 -----------------------------------
 
-``req.ttl`` had been previously listed as deprecated, but it is now
-fully supported, since there are use cases that cannot be solved
-without it.
+``req.grace`` had been previously removed, but was now reintroduced,
+since there are use cases that cannot be solved without it. Similarly,
+``req.ttl`` used to be deprecated and is now fully supported again.
 
 ``req.ttl`` and ``req.grace`` set upper bounds on the TTL and grace
 times that are permitted for the current request -- if these variables
 are set and the TTL/grace of a cache object is longer than their
 settings, then a new response is fetched from the backend, despite the
-presence of the response in the cache.
+presence of an otherwise fresh cache object.
 
 A common application is to set shorter TTLs when the backend is known
 to be healthy, so that responses are fresher when all is well. But if