intro/matplotlib/matplotlib.rst: remove trailing whitespace
intro/matplotlib/matplotlib.rst: syntax fixes
added the :class: directive, but something with intersphinx is still bust...
Merge branch 'minor_fixes/intro/matplotlib'

* minor_fixes/intro/matplotlib:
  added the :class: directive, but something with intersphinx is still bust...
  intro/matplotlib/matplotlib.rst: syntax fixes
  intro/matplotlib/matplotlib.rst: remove trailing whitespace