documentation symfony#3087 [Autocomplete] Add documentation about plugins management (raphael-geffroy)

This PR was merged into the 2.x branch.

Discussion
----------

[Autocomplete] Add documentation about plugins management

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| Docs?         | yes
| Issues        | Fix symfony#3057
| License       | MIT

Commits
-------

4ccf5f6 [Autocomplete] Add documentation about plugins management

Author: Kocal

src/Autocomplete/doc/index.rst

@@ -206,6 +206,7 @@ e.g. ``FoodAutocompleteField`` from above):
 ``tom_select_options`` (default: ``[]``)
     Use this to set custom `Tom Select Options`_. If you need to set
     an option using JavaScript, see `Extending Tom Select`_.
+    Read also about `Managing plugins`_.
 
 ``options_as_html`` (default: ``false``)
     Set to ``true`` if your options (e.g. ``choice_label``) contain HTML. Not
@@ -415,6 +416,36 @@ all of the options - separated by the ``delimiter`` - will be sent as a string.
 You *can* add autocompletion to this via the ``autocomplete_url`` option - but you'll
 likely need to create your own :ref:`custom autocomplete endpoint <custom-autocomplete-endpoint>`.
 
+Managing plugins
+----------------
+
+`Tom Select Plugins`_ can be configured through the ``tom_select_options.plugins`` option:
+
+    $resolver->setDefaults([
+        'class' => Ingredient::class,
+        'tom_select_options' => [
+            'plugins' => [
+                // Enable Input Autogrow plugin
+                'input_autogrow',
+
+                // Enable Dropdown Header plugin, with custom configuration
+                'dropdown_header' => [
+                    'title' => 'Select an ingredient',
+                ],
+
+                // Force natively-enabled plugins (by UX Autocomplete) to be disabled
+                'clear_button' => false,
+                'remove_button' => false,
+            ],
+        ],
+    ]);
+
+.. note::
+
+    Some configuration could not be supported through the `tom_select_options.plugins` option,
+    for example when a plugin requires a JavaScript function as configuration value.
+    In that case, you must use the `Extending Tom Select`_ approach to configure plugins.
+
 Customizing the AJAX URL/Route
 ------------------------------
 
@@ -758,3 +789,4 @@ the Symfony framework: https://symfony.com/doc/current/contributing/code/bc.html
 .. _`Tom Select Option Group`: https://tom-select.js.org/examples/optgroups/
 .. _`Symfony Form`: https://symfony.com/doc/current/forms.html
 .. _`@symfony/ux-autocomplete npm package`: https://www.npmjs.com/package/@symfony/ux-autocomplete
+.. _`Tom Select Plugins`: https://tom-select.js.org/plugins/