Merge branch '3.x' into 4.x

* 3.x:
  Add an additional example in the docs
  Fix ignored parenthesis in expressions
  Tweak previous merge
  Added details in the doc of filters and functions of IntlExtension
  Add more information about the filter and the negative operators
  Update plural.rst: Fixing filter name

src/ExpressionParser.php

@@ -167,7 +167,12 @@ class ExpressionParser
             $expr = $this->parseExpression();
             $this->parser->getStream()->expect(Token::PUNCTUATION_TYPE, ')', 'An opened parenthesis is not properly closed');
 
-            return $this->parsePostfixExpression($expr);
+            $expr = $this->parsePostfixExpression($expr);
+            if ($expr instanceof NegUnary) {
+                $expr->wrapInParentheses();
+            }
+
+            return $expr;
         }
 
         return $this->parsePrimaryExpression();