Issue #3330549: Update readme.md file format

README.md

-CONTENTS OF THIS FILE
----------------------
-
- * Introduction
- * Requirements
- * Installation
- * Configuration
- * Maintainers
-
-
-INTRODUCTION
-------------
+# Views Fieldsets
 
 Creates fieldset (and details and div) in Views fields output, to group fields,
 by adding a new field: "Global: Fieldset" and a few preprocessors. Also
 introduces a new template: views-fieldsets-fieldset.tpl.php where you can
 customize your fieldset output.
 
- * For a full description of the module, visit the project page:
-   https://www.drupal.org/project/views_fieldsets
+For a full description of the module, visit the
+[project page](https://www.drupal.org/project/admin_menu).
 
- * To submit bug reports and feature suggestions, or to track changes:
-   https://www.drupal.org/project/issues/views_fieldsets
+Submit bug reports and feature suggestions, or track changes in the
+[issue queue](https://www.drupal.org/project/issues/admin_menu).
 
 
-REQUIREMENTS
-------------
+## Table of contents
 
-This module requires no modules outside of Drupal core.
+- Requirements
+- Installation
+- Configuration
+- Maintainers
 
+## Requirements
 
-INSTALLATION
-------------
+This module requires no modules outside of Drupal core.
+
+## Installation
 
- * Install the Views fieldsets module as you would normally install a
-   contributed Drupal module. Visit
-   https://www.drupal.org/node/1897420 for further information.
+Install as you would normally install a contributed Drupal module. For further
+information, see
+[Installing Drupal Modules](https://www.drupal.org/docs/extending-drupal/installing-drupal-modules).
 
 
-CONFIGURATION
--------------
+## Configuration
 
-    1. Navigate to Administration > Extend and enable the module.
-    2. Navigate to Administration > Structure > views and open existing view or
-       a create a new view.
-    3. Add some fields.
-    4. Add field "Global: Fieldset" and customize settings (html tag,
-       collapsible, tokens etc)
-    5. Rearrange fields to drag normal fields under Fieldset fields. You can
-       nest fieldsets. The result will be visible in Preview.
+1. Navigate to Administration > Extend and enable the module.
+2. Navigate to Administration > Structure > views and open existing view or
+   a create a new view.
+3. Add some fields.
+4. Add field "Global: Fieldset" and customize settings (html tag,
+   collapsible, tokens etc)
+5. Rearrange fields to drag normal fields under Fieldset fields. You can
+   nest fieldsets. The result will be visible in Preview.
 
 Theming:
 There are several new templates. You can specify the filename the Views way. See
 Theme: Information for theme hook suggestion specifics. Available:
 
- * views-fieldsets-fieldset.tpl.php
- * views-fieldsets-fieldset--events.tpl.php
- * views-fieldsets-fieldset--default.tpl.php (all tags)
- * views-fieldsets-fieldset--default.tpl.php (per tag)
- * views-fieldsets-fieldset--page.tpl.php
- * views-fieldsets-fieldset--events--page.tpl.php
- 
+- views-fieldsets-fieldset.html.twig
+- views-fieldsets-fieldset--events.html.twig
+- views-fieldsets-fieldset--default.html.twig (all tags)
+- views-fieldsets-fieldset--default.html.twig (per tag)
+- views-fieldsets-fieldset--page.html.twig
+- views-fieldsets-fieldset--events--page.html.twig
+
 And of course the related preprocessors:
 
 ```
@@ -67,12 +59,10 @@ template_preprocess_views_fieldsets_fieldset(),
 template_preprocess_views_fieldsets_fieldset__events() etc.
 ```
 
+## Maintainers
 
-MAINTAINERS
------------
-
- * rudiedirkx - https://www.drupal.org/u/rudiedirkx
+- rudiedirkx (rudiedirkx) - https://www.drupal.org/u/rudiedirkx
 
 Supporting organizations:
 
- * GOLEMS GABB - https://www.drupal.org/golems-gabb
+- GOLEMS GABB (golems-gabb) - https://www.drupal.org/golems-gabb