Make sorting documentation more clear

Author: jaladh-singhal

docs/usage/viewing-tables.rst

@@ -22,7 +22,7 @@ without showing the table in the viewer, use :meth:`FireflyClient.fetch_table`:
 
     fc.fetch_table(file_on_server=tval, tbl_id='invisible-table')
 
-Alternatively, you can turn off the `visible` parameter in :meth:`FireflyClient.fetch_table`:
+Alternatively, you can turn off the `visible` parameter in :meth:`FireflyClient.show_table`:
 
 .. code-block:: py
 
@@ -67,3 +67,5 @@ order:
 .. code-block:: py
     
     fc.sort_table_column(tbl_id=tbl_id_2mass_psc, column_name='j_m', sort_direction='ASC')
+
+If a column has sorting, it can be removed by specifying `sort_direction=''`.

firefly_client/firefly_client.py

@@ -1952,8 +1952,8 @@ def sort_table_column(self, tbl_id, column_name, sort_direction=''):
         column_name : `str`
             Name of the table column to sort
         sort_direction : {'', 'ASC', 'DESC'}, optional
-            Direction of sort: '' for unsorted, 'ASC' for ascending, and 'DESC'
-            for descending. Default is ''.
+            Direction of sort: '' for unsorted (or for removing the sort), 
+            'ASC' for ascending, and 'DESC' for descending. Default is ''.
 
         Returns
         --------