Make doc compiling under windows workable
The doc generation failed under windows due to problems with sphinx
and encoded umlauts in code (see links in
https://github.com/pydata/pandas/issues/5142).

The workaround is to replace the offending text with one which does not fail
(but which makes the example a bit pointless), build the docs and restore the
old text.

Closes: #5142

2 things:
1. Can you add a comment to the doc fixing code that says 'Sphinx fails on embedded unicode on Windows'.
2. Can you make the comment show up only on Windows? Eg put it with the replacement? I think it would be cleaner.
 @jtratner like this?
 Please remove this PR, I think I found the real cause of the failing doc builds
