minor #377 Add information about the query search string when creating custom co… (maartendekeizer, weaverryan)

This PR was merged into the 2.x branch.

Discussion
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Add information about the query search string when creating custom co…

…ntrollers

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| Tickets       | n/a
| License       | MIT

I was looking how to know what the user was looking (what the user typed). Easy to find with a debug bar, but I think it should be part of the documentation.

Commits
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85a411d removing extra word
b48aa4d Use text suggestion from `@weaverryan`
1b7f0f7 Add information about the query search string when creating custom controllers

Author: weaverryan

src/Autocomplete/src/Resources/doc/index.rst

@@ -483,6 +483,7 @@ a :ref:`custom autocompleter <custom-autocompleter>`:
     Once you have this, generate the URL to your controller and
     pass it to the ``url`` value of the ``stimulus_controller()`` Twig
     function, or to the ``autocomplete_url`` option of your form field.
+    The search term entered by the user is passed as a query parameter called ``query``.
 
 Beyond ``url``, the Stimulus controller has various other values,
 including ``tomSelectOptions``. See the `controller.ts`_ file for