In https://github.com/matplotlib/matplotlib/pull/7025/files#diff-d16d8f2163ade22dd20a465382c64881R148 I added some unicode to the docs which is not well handled by the latex. It causes an error (which can be ignored by typing 'R' into the prompt) when bulding the docs.

That example could be fixed by:

• removing the offending lines
• sorting out how to make latex deal with Chinese characters
• html-only that block