fix sponsors page (#640)

Author: solegalli

docs/donate.rst

@@ -27,38 +27,8 @@ the following sponsors:
 
 |
 
-.. raw:: html
-
-   </div>
-   </div>
-
-........
-
-.. raw:: html
-
-   <div class="sk-sponsor-div">
-   <div class="sk-sponsor-div-box">
-
-Feature-engine was originally conceived at `Train in Data <https://www.trainindata.com/>`_,
-and it is constantly updated as we develop our courses.
-
-.. raw:: html
-
-   </div>
-
-   <div class="sk-sponsor-div-box">
-
 .. image:: images/sponsors/trainindata.png
-   :width: 150pt
+   :width: 200pt
    :align: center
    :target:  https://www.trainindata.com/
 
-.. raw:: html
-
-   </div>
-   </div>
-
-..........
-
-|
-|