[docs] Fix typo in simple memo example

CHANGELOG.md

@@ -5,6 +5,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Fixed
+- Fixed a typo in simple memo example in the documentation. ([#121](https://github.com/jstockwin/py-pdf-parser/pull/121))
 
 ## [0.5.0] - 2020-07-05
 ### Added

docs/source/examples/simple_memo.rst

@@ -47,7 +47,7 @@ We will extract the "TO:", "FROM:", "DATE:" and "SUBJECT:" elements as reference
 .. image:: /screenshots/simple_memo_example/top.png
    :height: 200px
 
-To extract the element which says "TO:", we can simply run :meth:`document.elements.filter_by_font("TO:") <py_pdf_parser.filtering.ElementList.filter_by_font>`. This returns a new :class:`~py_pdf_parser.filtering.ElementList` which contains all the elements in the document with text equal to "TO:". In this case, there should only be one element in the list. We could just use ``[0]`` on the element list to access the element in question, however, there is a convenience function, :func:`~py_pdf_parser.filtering.ElementList.extract_single_element` on the :class:`~py_pdf_parser.filtering.ElementList` class to handle this case. This essentially checks if the list has a single element and returns the element for you, otherwise it raises an exception. Use of this is encouraged to make your code more robust and to make any errors more explicit.
+To extract the element which says "TO:", we can simply run :meth:`document.elements.filter_by_text_equal("TO:") <py_pdf_parser.filtering.ElementList.filter_by_text_equal>`. This returns a new :class:`~py_pdf_parser.filtering.ElementList` which contains all the elements in the document with text equal to "TO:". In this case, there should only be one element in the list. We could just use ``[0]`` on the element list to access the element in question, however, there is a convenience function, :func:`~py_pdf_parser.filtering.ElementList.extract_single_element` on the :class:`~py_pdf_parser.filtering.ElementList` class to handle this case. This essentially checks if the list has a single element and returns the element for you, otherwise it raises an exception. Use of this is encouraged to make your code more robust and to make any errors more explicit.
 
 .. code-block:: python