Mark execCommand etc as deprecated & non-standard (#5518)

This change marks the following as deprecated & non-standard:

* document.execCommand()
* document.queryCommandEnabled()
* document.queryCommandState()
* document.queryCommandSupported()

None are defined in any specification that is on the standards track.
Instead, https://w3c.github.io/editing/execCommand.html documents them,
but has a big red warning with the following text:

> This spec is incomplete and it is not expected that it will advance
> beyond draft status. Authors should not use most of these features
> directly, but instead use JavaScript editing libraries. The features
> described in this document are not implemented consistently or fully by
> user agents, and it is not expected that this will change in the
> foreseeable future.

api/Document.json

@@ -3777,8 +3777,8 @@
           },
           "status": {
             "experimental": false,
-            "standard_track": true,
-            "deprecated": false
+            "standard_track": false,
+            "deprecated": true
           }
         },
         "ClearAuthenticationCache": {
@@ -8538,8 +8538,8 @@
           },
           "status": {
             "experimental": false,
-            "standard_track": true,
-            "deprecated": false
+            "standard_track": false,
+            "deprecated": true
           }
         }
       },
@@ -8634,8 +8634,8 @@
           },
           "status": {
             "experimental": false,
-            "standard_track": true,
-            "deprecated": false
+            "standard_track": false,
+            "deprecated": true
           }
         }
       },
@@ -8696,8 +8696,8 @@
           },
           "status": {
             "experimental": false,
-            "standard_track": true,
-            "deprecated": false
+            "standard_track": false,
+            "deprecated": true
           }
         }
       },