migration symfony 5 4 (#300)

* symfony 5.4 (diff dev)

* symfony 5.4 (working)

* symfony 5.4 (update autoload)

* symfony 5.4 (remove swiftmailer mailer implementation)

* symfony 5.4 (php doc and split Global accessor class)


### Impacted packages:

composer require php:">=7.2.5 <8.0.0" symfony/console:5.4.* symfony/dotenv:5.4.* symfony/framework-bundle:5.4.* symfony/twig-bundle:5.4.* symfony/yaml:5.4.* --update-with-dependencies

composer require symfony/stopwatch:5.4.* symfony/web-profiler-bundle:5.4.* --dev --update-with-dependencies

lib/symfony/css-selector/Parser/Tokenizer/TokenizerEscaping.php

@@ -30,36 +30,21 @@ class TokenizerEscaping
         $this->patterns = $patterns;
     }
 
-    /**
-     * @param string $value
-     *
-     * @return string
-     */
-    public function escapeUnicode($value)
+    public function escapeUnicode(string $value): string
     {
         $value = $this->replaceUnicodeSequences($value);
 
         return preg_replace($this->patterns->getSimpleEscapePattern(), '$1', $value);
     }
 
-    /**
-     * @param string $value
-     *
-     * @return string
-     */
-    public function escapeUnicodeAndNewLine($value)
+    public function escapeUnicodeAndNewLine(string $value): string
     {
         $value = preg_replace($this->patterns->getNewLineEscapePattern(), '', $value);
 
         return $this->escapeUnicode($value);
     }
 
-    /**
-     * @param string $value
-     *
-     * @return string
-     */
-    private function replaceUnicodeSequences($value)
+    private function replaceUnicodeSequences(string $value): string
     {
         return preg_replace_callback($this->patterns->getUnicodeEscapePattern(), function ($match) {
             $c = hexdec($match[1]);