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/TokenStream.php

@@ -56,7 +56,7 @@ class TokenStream
      *
      * @return $this
      */
-    public function push(Token $token)
+    public function push(Token $token): self
     {
         $this->tokens[] = $token;
 
@@ -68,7 +68,7 @@ class TokenStream
      *
      * @return $this
      */
-    public function freeze()
+    public function freeze(): self
     {
         return $this;
     }
@@ -76,11 +76,9 @@ class TokenStream
     /**
      * Returns next token.
      *
-     * @return Token
-     *
      * @throws InternalErrorException If there is no more token
      */
-    public function getNext()
+    public function getNext(): Token
     {
         if ($this->peeking) {
             $this->peeking = false;
@@ -98,10 +96,8 @@ class TokenStream
 
     /**
      * Returns peeked token.
-     *
-     * @return Token
      */
-    public function getPeek()
+    public function getPeek(): Token
     {
         if (!$this->peeking) {
             $this->peeked = $this->getNext();
@@ -116,19 +112,17 @@ class TokenStream
      *
      * @return Token[]
      */
-    public function getUsed()
+    public function getUsed(): array
     {
         return $this->used;
     }
 
     /**
-     * Returns nex identifier token.
-     *
-     * @return string The identifier token value
+     * Returns next identifier token.
      *
      * @throws SyntaxErrorException If next token is not an identifier
      */
-    public function getNextIdentifier()
+    public function getNextIdentifier(): string
     {
         $next = $this->getNext();
 
@@ -140,13 +134,11 @@ class TokenStream
     }
 
     /**
-     * Returns nex identifier or star delimiter token.
-     *
-     * @return string|null The identifier token value or null if star found
+     * Returns next identifier or null if star delimiter token is found.
      *
      * @throws SyntaxErrorException If next token is not an identifier or a star delimiter
      */
-    public function getNextIdentifierOrStar()
+    public function getNextIdentifierOrStar(): ?string
     {
         $next = $this->getNext();