API Remove deprecated FormAction::createTag()

docs/en/04_Changelogs/4.0.0.md

@@ -1319,6 +1319,7 @@ A very small number of methods were chosen for deprecation, and will be removed
   * `BigSummary` is removed. Use `Summary` instead.
   * Most limit methods on `DBHTMLText` now plain text rather than attempt to manipulate the underlying HTML.
 * `FormField::Title` and `FormField::RightTitle` are now cast as plain text by default (but can be overridden).
+* `FormField#createTag()` has been renamed to `FormField::create_tag()`  
 * `Hierarchy` class has had much of it's functionality refactored out into `MarkedSet`:
   * `isMarked`
   * `isTreeOpened`

src/Forms/FormField.php

@@ -1260,22 +1260,6 @@ class FormField extends RequestHandler
         return strtolower(preg_replace('/Field$/', '', $type->getShortName()));
     }
 
-    /**
-     * @deprecated 4.0 Use FormField::create_tag()
-     *
-     * @param string $tag
-     * @param array $attributes
-     * @param null|string $content
-     *
-     * @return string
-     */
-    public function createTag($tag, $attributes, $content = null)
-    {
-        Deprecation::notice('4.0', 'Use FormField::create_tag()');
-
-        return self::create_tag($tag, $attributes, $content);
-    }
-
     /**
      * Abstract method each {@link FormField} subclass must implement, determines whether the field
      * is valid or not based on the value.