Merge branch '6.0' into 6.1

* 6.0:
  [LokaliseBridge] Fix push command --delete-missing options when there are no missing messages
  fix bad help message in cache warmup command
  [Console] Fix OutputFormatterStyleStack::getCurrent return type
  Count cookie parts before accessing the second
  Fix RequestStack state if throwable is thrown
  [Serializer] Fix caching context-aware encoders/decoders in ChainEncoder/ChainDecoder

Author: fabpot

Formatter/OutputFormatterStyleStack.php

@@ -77,7 +77,7 @@ public function pop(OutputFormatterStyleInterface $style = null): OutputFormatte
     /**
      * Computes current style with stacks top codes.
      */
-    public function getCurrent(): OutputFormatterStyle
+    public function getCurrent(): OutputFormatterStyleInterface
     {
         if (empty($this->styles)) {
             return $this->emptyStyle;