Add legend.titlesize to example rc file

[kilojoules]

No description provided.

[ImportanceOfBeingErnest]

Note that this is the documentation repo. It is more or less just the host for the webpage. Changes need to go into the source repo at github.com/matplotlib/matplotlib.

Second, note that legend.titlesize is not a valid rc parameter. You probably mean legend.title_fontsize. This parameter already is part of the rc file

https://github.com/matplotlib/matplotlib/blob/dbaf19d6410d3c92656787405ee4238b271c53c2/matplotlibrc.template#L423

So the _static/matplotlibrc file here is hence an old version of the real rc file that is continuously updated.

The real question would be: Can we safely delete this file or is it accessed from anywhere?

[QuLogic]

It was used with literalinclude to fill out https://matplotlib.org/tutorials/introductory/customizing.html, but it's since been moved to point to matplotlibrc.template. The only reference to this file is now in documentation about writing documentation. We should probably delete, but that's basically part the larger project of deleting/redirecting old files.

As this repo is not the source for this file, I am going to close this PR.

[kilojoules]

@ImportanceOfBeingErnest Just FYI the first thing that comes up from a search is https://matplotlib.org/users/customizing.html#matplotlib-rcparams, which does not include the title_fontsize option.