Remove non-applicable FIXMEs

- There is no way to distinguish between `?a=` and `?a` when rebuilding
  a query string.
- The further encoding of query delimiters (`=` and `&` in query
  _values_ is entirely normal and expected.

tests/test_url_query.py

@@ -16,10 +16,6 @@
         URL("http://example.com"),
         MultiDict(),
     ),
-    (
-        URL("http://example.com?a"),
-        MultiDict([("a", "")]),
-    ),
     (
         URL("http://example.com?a="),
         MultiDict([("a", "")]),
@@ -69,9 +65,7 @@ def test_query_basic_parsing(original_url, expected_query):
 )
 def test_query_basic_update_query(original_url, expected_query):
     new_url = original_url.update_query({})
-    # FIXME: `?a` becomes `?a=` right now. Maybe support `None` values?
-    # assert new_url == original_url
-    assert new_url is not None
+    assert new_url == original_url
 
 
 def test_query_dont_unqoute_twice():
@@ -162,6 +156,3 @@ def test_query_from_empty_update_query(
 
     if "b" in original_url.query:
         assert new_url.query["b"] == original_url.query["b"]
-
-    # FIXME: Broken because of asymmetric query encoding
-    # assert new_url == original_url