Docs: Add query to Query DSL documentation

We already introduced the MatchNoneQueryBuilder query that does not
return any documents, mainly because we needed it for internal
representation of the NONE option in the IndicesQueryBuilder.
However, the query was requested at least once also for the query dsl,
and since we can parser it already we should document it as
`match_none` query in the relevant reference docs as well.

docs/reference/query-dsl/match-all-query.asciidoc

@@ -15,3 +15,14 @@ The `_score` can be changed with the `boost` parameter:
 --------------------------------------------------
 { "match_all": { "boost" : 1.2 }}
 --------------------------------------------------
+
+[[query-dsl-match-none-query]]
+[float]
+== Match None Query
+
+This is the inverse of the `match_all` query, which matches no documents.
+
+[source,js]
+--------------------------------------------------
+{ "match_none": {} }
+--------------------------------------------------