Add documentation for "has" matcher on embedded objects (#1422)

Author: mareq

docs/release-source/release/matchers.md

@@ -12,13 +12,18 @@ corresponding `sinon.assert` functions as well as `spy.withArgs`. Matchers allow
     var book = {
         pages: 42,
         author: "cjno"
+        id: {
+          isbn10: "0596517742",
+          isbn13: "978-0596517748"
+        }
     };
     var spy = sinon.spy();
 
     spy(book);
 
     sinon.assert.calledWith(spy, sinon.match({ author: "cjno" }));
     sinon.assert.calledWith(spy, sinon.match.has("pages", 42));
+    sinon.assert.calledWith(spy, sinon.match.has("id", sinon.match.has("isbn13", "978-0596517748")));
 }
 ```
 

test/match-test.js

@@ -555,6 +555,16 @@ describe("sinonMatch", function () {
                 assert(has.test({ prop: symbol }));
             }
         });
+
+        it("returns true if embedded object has Symbol", function () {
+            if (typeof Symbol === "function") {
+                var symbol = Symbol();
+
+                var has = sinonMatch.has("prop", sinonMatch.has("embedded", symbol));
+
+                assert(has.test({ prop: { embedded: symbol }, ignored: 42 }));
+            }
+        });
     });
 
     describe(".hasOwnSpecial", function () {