Mark ShadowRoot.p.delegatesFocus standard & undeprecated

whatwg/dom#974 added ShadowRoot.prototype.delegatesFocus
to the DOM spec (see whatwg/dom@f346858). And
per whatwg/dom#931 (comment)
(https://trac.webkit.org/r276585) it’s been implemented in WebKit.

So given that it’s now part of the DOM standard, and implemented in multiple
browsers, this change resets the BCD status flags for it.

Related MDN change: mdn/content#4508

api/ShadowRoot.json

@@ -89,9 +89,9 @@
             }
           },
           "status": {
-            "experimental": true,
-            "standard_track": false,
-            "deprecated": true
+            "experimental": false,
+            "standard_track": true,
+            "deprecated": false
           }
         }
       },