Smarter detection of toctree elements

[javiereguiluz]

Related to this: symfony/symfony-docs#16302

In Sphinx we could do this:

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----------
.. toctree::
    :maxdepth: 1
    :glob:

    /console
    /components/console/*
    /components/console/helpers/index
    /console/*

Sphinx recognizes that you have added /components/console/helpers/index explicitly and then it doesn't include it repeatedly in /components/console/*

When using Docs Builder, we must do this change:

 Learn more
 ----------
 .. toctree::
     :maxdepth: 1
     :glob:

     /console
     /components/console/*
-    /components/console/helpers/index
     /console/*

This is not an essential feature, but it's nice when you want to include some specific article behind all the other articles.