add text formatting postprocessing functionality

[pickleerik]

A lot of the context is taken by key names. Here is an example of how we format the context:

## Table `"Match"`
 - ``id`` (INTEGER) No duplicates. No NULLs. Between 1.0 and 25979.0 (mean = 12990.0). 
 - ``country_id`` (INTEGER) 11 unique values. No NULLs. 
 - ``league_id`` (INTEGER) 11 unique values. No NULLs. 
 - ``season`` (TEXT) 8 unique values. No NULLs. Constant 9 chars.  May contain: only lowercase chars, numbers, punctuation. Common values: 2015/2016, 2008/2009, 2014/2015, 2012/2013, 2010/2011.
 - ``stage`` (INTEGER) 38 unique values. No NULLs. Between 1.0 and 38.0 (mean = 18.2). Common values: 6, 5, 4, 3, 2.
 - ``date`` (TEXT) 1694 unique values. No NULLs. Constant 19 chars.  May contain: only lowercase chars, numbers, punctuation. Common values: 2009-04-11 00:00:00, 2015-04-04 00:00:00, 2013-03-30 00:00:00, 2009-05-16 00:00:00, 2010-04-03 00:00:00.