bug #4032 Add twig_escape_filter_is_safe() as deprecated. (brummbar)

This PR was squashed before being merged into the 3.x branch.

Discussion
----------

Add twig_escape_filter_is_safe() as deprecated.

Fix for #4031

Commits
-------

1170144 Add twig_escape_filter_is_safe() as deprecated.

src/Resources/escaper.php

@@ -11,9 +11,11 @@
 
 use Twig\Environment;
 use Twig\Extension\EscaperExtension;
+use Twig\Node\Node;
 
 /**
  * @internal
+ *
  * @deprecated since Twig 3.9
  */
 function twig_raw_filter($string)
@@ -25,6 +27,7 @@ function twig_raw_filter($string)
 
 /**
  * @internal
+ *
  * @deprecated since Twig 3.9
  */
 function twig_escape_filter(Environment $env, $string, $strategy = 'html', $charset = null, $autoescape = false)
@@ -33,3 +36,15 @@ function twig_escape_filter(Environment $env, $string, $strategy = 'html', $char
 
     return EscaperExtension::escape($env, $string, $strategy, $charset, $autoescape);
 }
+
+/**
+ * @internal
+ *
+ * @deprecated since Twig 3.9
+ */
+function twig_escape_filter_is_safe(Node $filterArgs)
+{
+    trigger_deprecation('twig/twig', '3.9', 'Using the internal "%s" function is deprecated.', __FUNCTION__);
+
+    return EscaperExtension::escapeFilterIsSafe($filterArgs);
+}