* Rectified plot error

The plot shown on the page: https://matplotlib.org/tutorials/introductory/usage.html#sphx-glr-tutorials-introductory-usage-py

Will be possible only if plt.show() is outside the loop

* Added corrections in docs as per requirements

* Commented the code block to remove plot rendering

* Added ::

* corrected trailing spaces and bad indentation

* Removed E402

…abels

FIX: colorbar re-check norm before draw for autolabels

When plotting 10000 lines, this gives a ~10% improvement in performance.

If there's no margin to be added, we don't need sticky edges, but if
autoscaling is off, we _also_ don't need the sticky edges. This saves a
lot of time when plotting many artists, like in matplotlib#12542.

Avoid quadratic behavior when accumulating stickies.

Disable sticky edge accumulation if no autoscaling.

…ription

Doc: Clarify horizontalalignment and verticalalignment in suptitle

…nto hist2d_density

* 'hist2d_density' of https://github.com/thoo/matplotlib:
  Add density in hist2d