sphinx-copybutton does not copy empty lines

[amotl]

Hi there,

we are observing the problem mentioned at executablebooks/sphinx-copybutton#84 here.

For example, the code block at [1] will not get copied "as-is", all empty lines are missing. The config entries within conf.py we are currently using can be reviewed at [2].

With kind regards,
Andreas.

[1] https://crate.io/docs/python/en/latest/sqlalchemy.html#tables
[2] https://github.com/crate/crate-docs-theme/blob/0.15.1/src/crate/theme/rtd/conf/__init__.py#L112-L115

[amotl]

executablebooks/sphinx-copybutton#127 and #288 will resolve this situation.