refactor docs example table outputs

[CrepeGoat]

Copied & edited from #107

Some of the pandas DataFrame outputs in the docs have a lack of visual distinction between the table's formatting and the pain text formatting. E.g., in the below snippet from the docs (see the section "endaq.ide Usage Examples"), the last line "The results can be filtered by measurement type:" bleeds together with the table above it:

Instead, that table could be included in a pycon block, so that the command and it's output are both stylistically wrapped in a code-style block. (This done in the pandas docs quite a bit, though the tables tend to be smaller which may make this technique more feasible in their case.)

Using a pycon block would look something like this in the docstrings:

.. code:: pycon

    >>> get_channel_table(doc)
    ...