Issue #2565669 by plach: Update Twig to 1.21.2

core/composer.lock

core/vendor/composer/installed.json

core/vendor/twig/twig/CHANGELOG

core/vendor/twig/twig/doc/filters/merge.rst

core/vendor/twig/twig/doc/filters/sort.rst

core/vendor/twig/twig/doc/recipes.rst

core/vendor/twig/twig/ext/twig/php_twig.h

core/vendor/twig/twig/lib/Twig/Environment.php

core/vendor/twig/twig/lib/Twig/ExpressionParser.php

core/vendor/twig/twig/lib/Twig/Extension/Core.php

...ndor/twig/twig/lib/Twig/FileExtensionEscapingStrategy.php

...wig/test/Twig/Tests/FileExtensionEscapingStrategyTest.php

...dor/twig/twig/test/Twig/Tests/Fixtures/filters/merge.test

...r/twig/twig/test/Twig/Tests/Fixtures/filters/replace.test

...test/Twig/Tests/Fixtures/filters/replace_invalid_arg.test

...ndor/twig/twig/test/Twig/Tests/Fixtures/filters/sort.test