use pygment to stylize the docs code-blocks

[2bndy5]

I noticed an inconsistency in 1 of the doc's code-blocks under Progress Display->Table Columns.

Actually, the first thing that caught my eye was a missing backtick ( ` ) in the rst reference for the Tables class (missing before the tilda ~).

But then I noticed all the code blocks are written like quoted blocks (just an extra indent without the
.. code-block:: python directive). Since this lib emphasizes style, why not add some flare to the code-blocks in the docs. You can even specify your own pygment style to use in the conf.py (I monkey-patched a "dark-plus" style into my docs - see example)

p.s. there's also a nifty Sphinx extension that adds a "copy" button to all code-blocks in the docs

[willmcgugan]

Fixed the table columns section.

All the code blocks are syntax highlighted that I can see.

I like that copy button extension, I might use that.