[DOCS] Update linkvalidator documentation Introduction

The Introduction page is updated to reflect current master.
The text are changed in a way that they also apply for
previous versions 10 and 9.

Screenshots are replaced.

Resolves: #92691
Releases: master, 10.4, 9.5
Change-Id: I9eb633f5446dc08636f97548920a6419b1fe8359
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/66263


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Benni Mack <benni@typo3.org>

typo3/sysext/linkvalidator/Documentation/Introduction/Index.rst

@@ -38,7 +38,8 @@ It includes the following features:
   links to pages and content elements, file links to files in the local
   file system and external links to files somewhere else in the web.
 
-- Linkvalidator by default looks into header fields and bodytext fields.
+- Linkvalidator checks a number of fields by default, for example
+  header fields and bodytext fields of content elements.
   It can be configured to check any field you like.
 
 - Linkvalidator offers a just in time check of your website.
@@ -47,8 +48,8 @@ It includes the following features:
   email report, if broken links were found.
 
 - Linkvalidator is extendable. It provides hooks to check special types
-  of links like those from the extension "linkhandler". The possibility
-  to check these already is built in.
+  of links or override how the checking of external, file and page
+  links works.
 
 
 .. _screenshots:
@@ -94,9 +95,14 @@ Linkvalidator features full support of the TYPO3 scheduler. This is
 the linkvalidator task:
 
 .. figure:: ../Images/SchedulerTask.png
-   :alt: The linkvalidator scheduler task
+   :alt: The linkvalidator scheduler task (1)
 
-   Defining the linkvalidator task in the Scheduler
+   Defining the linkvalidator task in the Scheduler (2)
+
+.. figure:: ../Images/SchedulerTask2.png
+   :alt: The linkvalidator scheduler task (2)
+
+   Defining the linkvalidator task in the Scheduler (2)
 
 
 - With this task you can run linkvalidator regularly via cron without
@@ -107,9 +113,7 @@ the linkvalidator task:
   be used. If you set values there, the former will be overwritten.
 
 - The linkvalidator task can send you a status report via email. You can
-  create an own email template as needed. The default template is
-  located in typo3/sysext/linkvalidator/res/mailtemplate.html.
-
+  create your own email template as needed.
 
 .. _credits:
 
@@ -128,7 +132,6 @@ Feedback
 ^^^^^^^^
 
 If you find a bug in this manual or in the extension in general,
-please file an issue in the bug tracker of this extension:
-`https://forge.typo3.org/projects/extension-linkvalidator/issues
-<https://forge.typo3.org/projects/extension-linkvalidator/issues>`_
+please file an issue in the
+`TYPO3 bug tracker <https://forge.typo3.org/projects/typo3cms-core/issues>`__.