MDL-74160 core_coureformat: fix legacy renderer methods

To ensure legacy course formats works on Moodle 4.0 some method are
reintroduced (but marked as deprecated) like start_section_list and
end_section_list. Furthermore, the course_section_cm_availability
returns a string again as expected.

course/format/classes/output/section_renderer.php

@@ -413,6 +413,34 @@ protected function section_footer() {
         return $o;
     }
 
+    /**
+     * Generate the starting container html for a list of sections.
+     *
+     * @deprecated since 4.0 MDL-72656 - use core_course output components instead.
+     *
+     * @return string HTML to output.
+     */
+    protected function start_section_list() {
+        debugging('start_section_list() is deprecated. Please use ' .
+            'core_courseformat\\output\\local\\content\\section to render individual sections or .' .
+            'core_courseformat\\output\\local\\content to render the full course', DEBUG_DEVELOPER);
+        return html_writer::start_tag('ul', ['class' => 'sections']);
+    }
+
+    /**
+     * Generate the closing container html for a list of sections.
+     *
+     * @deprecated since 4.0 MDL-72656 - use core_course output components instead.y
+     *
+     * @return string HTML to output.
+     */
+    protected function end_section_list() {
+        debugging('end_section_list() is deprecated. Please use ' .
+            'core_courseformat\\output\\local\\content\\section to render individual sections or .' .
+            'core_courseformat\\output\\local\\content to render the full course', DEBUG_DEVELOPER);
+        return html_writer::end_tag('ul');
+    }
+
     /**
      * Old method to print section edit controls. Do not use it!
      *

course/renderer.php

@@ -823,10 +823,8 @@ public function course_section_cm_availability(cm_info $mod, $displayoptions = a
             $mod->get_section_info(),
             $mod,
         );
-
         $renderer = $format->get_renderer($this->page);
-        $data = $availability->export_for_template($renderer);
-        return $data->info ?? '';
+        return $renderer->render($availability);
     }
 
     /**

course/upgrade.txt

@@ -56,9 +56,9 @@ renderer and course format renderer:
   - course_section_cm_name_title (replaced by core_courseformat\output\local\cm\title)
   - course_section_cm_text (integrated in core_courseformat\output\local\content\cm)
   - course_section_cm_availability (replaced by core_courseformat\output\local\content\cm\availability))
-* The following abstract methods are deleted:
   - start_section_list (integrated in core_courseformat\output\local\content)
   - end_section_list (integrated in core_courseformat\output\local\content)
+* The following abstract methods are deleted:
   - page_title (moved to core_courseformat\output\local\content)
 * Course formats should have a renderer (until now it was only highly recommended but not mandatory). For backwards
 compatibility (to not break third-party plugins without it), legacy_format_renderer has been created and will be used when