Issue #2557411 by joelpittet: Remove obsolete reference to SafeMarkup::set()...

Issue #2557411 by joelpittet: Remove obsolete reference to SafeMarkup::set() in LinkGeneratorTest documentation

core/tests/Drupal/Tests/Core/Utility/LinkGeneratorTest.php

@@ -372,8 +372,8 @@ public function testGenerateWithHtml() {
     ), $result);
 
     // Test that safe HTML is output inside the anchor tag unescaped. The
-    // SafeMarkup::set() call is an intentional unit test for the interaction
-    // between SafeMarkup and the LinkGenerator.
+    // SafeString::create() call is an intentional unit test for the interaction
+    // between SafeStringInterface and the LinkGenerator.
     $url = new Url('test_route_5', array());
     $url->setUrlGenerator($this->urlGenerator);
     $result = $this->linkGenerator->generate(SafeString::create('<em>HTML output</em>'), $url);