DOC: copybutton does not copy complete example

[mosc9575]

What happened?

In the documentation sometimes the copy button fails to copy the complete example. One example can be seen in the HDF section

This is because the number of dots (4) are not matched by the regular expression of the copy button, this regular expression needs a small tweak.

To explain the problem in more detail, the io page uses ipython to run the example code and there are many cells. The regular expression

xarray/doc/conf.py

Line 100 in 10bb94c

copybutton_prompt_text = r">>> |\.\.\. |\$ |In \[\d*\]: | {2,5}\.\.\.: | {5,8}: "

is working working for the first 9 cells. If there is a double digit cell with a multi line example, the copy button does not work.
The regular expression looks for 3 dots ans a double dot. But for larger numbers there are the length of the number of the cell plus two dots.

[keewis]

interestingly enough, it looks like this has been the behavior of the ipython sphinx extension since 15 years ago, which deviates from what the ipython shell itself does (it left-pads with spaces). At least the sphinx extension makes sure all code cells are consistent, even the verbatim ones.