minor symfony#2788 [Icons] Docs: Removing broken link (ThomasLandauer)

This PR was squashed before being merged into the 2.x branch.

Discussion
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[Icons] Docs: Removing broken link

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| Docs?         | yes
| Issues        |
| License       | MIT

Page: https://symfony.com/bundles/ux-icons/current/index.html#locking-on-demand-icons

The target is just a few paragraphs above, so there's no need for a link IMO.

Commits
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0e58ef4 [Icons] Docs: Removing broken link

Author: smnandre

src/Icons/doc/index.rst

@@ -272,7 +272,7 @@ the ``assets/icons/`` directory. You can think of importing an icon as *locking
 Locking On-Demand Icons
 ~~~~~~~~~~~~~~~~~~~~~~~
 
-You can *lock* (import) all the `*on-demand* <Icons On-Demand>`_ icons you're using in your project by
+You can *lock* (import) all the *on-demand* icons you're using in your project by
 running the following command:
 
 .. code-block:: terminal