DOC: add semicolons to suppress text repr of matplotlib objects in visualization.rst
add semicolons (";") after the plotting function to suppress unnecessary debug messages similar to:

<matplotlib.axes._subplots.AxesSubplot at 0x7fe278bb5160>

- [ ] closes #xxxx
- [ ] tests added / passed
- [ ] passes `black pandas`
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

Is there a more generic way to do this? I think this is distracting for end users

@jorisvandenbossche  > I think this is distracting for end users

FWIW, I've seen this quite frequently in tutorials We indeed already do it in several places in visualization.rst itself (see https://pandas.pydata.org/docs/dev/user_guide/visualization.html), so this is making it more consistent. This pull request is stale because it has been open for thirty days with no activity. Please update or respond to this comment if you're still interested in working on this. @partev can you merge master and we can get this in @jreback done thanks @partev 

@jorisvandenbossche has a comment from above if you can have a look