embolden for the hard of thinking

Author: cjw296

README.rst

@@ -21,8 +21,8 @@ files in the historical ``.xls`` format.
 
 .. warning::
 
-  This library will no longer read anything other than ``.xls`` files. For
-  alternatives that read newer file formats, please see http://www.python-excel.org/.
+  **This library will no longer read anything other than ``.xls`` files. For
+  alternatives that read newer file formats, please see http://www.python-excel.org/.**
 
 The following are also not supported but will safely and reliably be ignored: