Use defun indentation type for treepy--context-assoc

[tarsius]

This helps avoiding long lines and looks better even in cases were the line length isn't a problem. An alternative that could be used to only deal with the long-line cases would be to place the first argument on a separate line, but that would waste vertical space, look odd, and would needlessly cause different uses of this function to look different.

[tarsius]

Friendly ping :smile:

[tarsius]

Cheers :heart: