minor #14074 [Templating] Explain the hinclude.js attributes (javiereguiluz)

This PR was squashed before being merged into the 4.4 branch.

Discussion
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[Templating] Explain the hinclude.js attributes

Recently it took me some time to learn how to run JS code in a content loaded via hinclude.js ... so I propose to add a short explanation about these attributes.

Commits
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8539dc5 [Templating] Explain the hinclude.js attributes

Author: javiereguiluz

templating/hinclude.rst

@@ -88,4 +88,16 @@ Or you can also specify a string to display as the default content:
 
     {{ render_hinclude(controller('...'), {default: 'Loading...'}) }}
 
+Use the ``attributes`` option to define the value of hinclude.js options:
+
+.. code-block:: twig
+
+    {# by default, cross-site requests don't use credentials such as cookies, authorization
+       headers or TLS client certificates; set this option to 'true' to use them
+    {{ render_hinclude(controller('...'), {attributes: {data-with-credentials: 'true'}}) }}
+
+    {# by default, the JavaScript code included in the loaded contents is not run;
+       set this option to 'true' to run that JavaScript code #}
+    {{ render_hinclude(controller('...'), {attributes: {evaljs: 'true'}}) }}
+
 .. _`hinclude.js`: http://mnot.github.io/hinclude/