Update doc/howdoi.rst

Suggestion from keewis

Co-Authored-By: keewis <[email protected]>

Author: rpgoldman

doc/howdoi.rst

@@ -12,7 +12,7 @@ How do I ...
    * - How do I...
      - Solution
    * - add a DataArray to my dataset as a new variable
-     - ``my_dataset[varname] = my_dataArray`` or :py:meth:`Dataset.assign`[#assign_dict]_
+     - ``my_dataset[varname] = my_dataArray`` or :py:meth:`Dataset.assign` (see also :ref:`dictionary_like_methods`)
    * - add variables from other datasets to my dataset
      - :py:meth:`Dataset.merge`
    * - add a new dimension and/or coordinate
@@ -62,4 +62,4 @@ How do I ...
 
 .. rubric:: Footnotes
 
-.. [#assign_dict] See also :ref:`dictionary_like_methods`:.
+.. [#assign_dict] See also :ref:`dictionary_like_methods`:.