minor #9220 [Workflow] PlantUML Dump documentation (Plopix)

This PR was submitted for the 4.0 branch but it was merged into the master branch instead (closes #9220).

Discussion
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[Workflow] PlantUML Dump documentation

Documentation related to symfony/symfony#24705
This PR aims to explain that the PlantUML dump format is available.

Platform.sh URL: http://pr-9220-x7nzdnq-6qmocelev2lwe.eu.platform.sh/workflow/dumping-workflows.html

Commits
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b62d961 [Workflow] PlantUML Dump documentation

Author: javiereguiluz

_images/components/workflow/blogpost_puml.png

@@ -5,31 +5,56 @@ How to Dump Workflows
 =====================
 
 To help you debug your workflows, you can dump a representation of your workflow
-with the use of a ``DumperInterface``. Use the ``GraphvizDumper`` to create a
-PNG image of the workflow defined above::
+or state machine with the use of a ``DumperInterface``. Symfony provides 2
+different dumpers both based on Dot.
 
-    // dump-graph.php
+Use the ``GraphvizDumper`` or ``StateMachineGraphvizDumper`` to create DOT
+files, or use ``PlantUmlDumper`` for PlantUML files. Both types can be converted
+to PNG images.
+
+Images of the workflow defined above:
+
+.. code-block:: php
+
+    // dump-graph-dot.php
     $dumper = new GraphvizDumper();
     echo $dumper->dump($definition);
 
+.. code-block:: php
+
+    // dump-graph-puml.php
+    $dumper = new PlantUmlDumper();
+    echo $dumper->dump($definition);
+
 .. code-block:: terminal
 
-    $ php dump-graph.php | dot -Tpng -o graph.png
+    $ php dump-graph-dot.php | dot -Tpng -o dot_graph.png
+    $ php dump-graph-puml.php | java -jar plantuml.jar -p  > puml_graph.png
 
-The result will look like this:
+The DOT result will look like this:
 
 .. image:: /_images/components/workflow/blogpost.png
 
-Inside a Symfony application, you can dump the dot file with the
+The PUML result:
+
+.. image:: /_images/components/workflow/blogpost_puml.png
+
+Inside a Symfony application, you can dump the files with those commands using
 ``workflow:dump`` command:
 
 .. code-block:: terminal
 
     $ php bin/console workflow:dump name | dot -Tpng -o graph.png
+    $ php bin/console workflow:dump name --dump-format=puml | java -jar plantuml.jar -p  > workflow.png
 
 .. note::
 
     The ``dot`` command is part of Graphviz. You can download it and read
     more about it on `Graphviz.org`_.
 
+    The ``plantuml.jar`` command is part of PlantUML. You can download it and
+    read more about it on `PlantUML.com`_.
+
+
 .. _Graphviz.org: http://www.graphviz.org
+.. _PlantUML.com: http://plantuml.com/