Merge branch '2.8' into 3.4

* 2.8:
  Another PR template tweak
  [PropertyInfo] ReflectionExtractor: give a chance to other extractors if no properties
  Clean calls to http_build_query()
  [WebProfilerBundle] limit ajax request to 100 and remove the last one
  [HttpFoundation] Fix missing "throw" in JsonResponse
  Improve the documentation of
  Suppress warning from sapi_windows_vt100_support on stream other than STDIO
  removed extra-verbose comments
  Fixes #26136: Avoid emitting warning in hasParameterOption()
  Added a README entry to the PR template
  [HttpFoundation] Add x-zip-compressed to MimeTypeExtensionGuesser.
  [DI] Add null check for removeChild

Author: nicolas-grekas

Form.php

@@ -209,7 +209,7 @@ public function getUri()
                 parse_str($query, $currentParameters);
             }
 
-            $queryString = http_build_query(array_merge($currentParameters, $this->getValues()), null, '&');
+            $queryString = http_build_query(array_merge($currentParameters, $this->getValues()), '', '&');
 
             $pos = strpos($uri, '?');
             $base = false === $pos ? $uri : substr($uri, 0, $pos);