DOC: fix spm_hrf_compat docstring
DOC: fix spm_hrf_compat docstring

The arguments were out of order in the docstring description.

arokem/nipy,alexis-roche/register,alexis-roche/register,arokem/nipy,nipy/nireg,alexis-roche/nireg,alexis-roche/niseg,alexis-roche/niseg,nipy/nireg,alexis-roche/nireg,alexis-roche/nipy,alexis-roche/nipy,alexis-roche/nipy,arokem/nipy,arokem/nipy,alexis-roche/register,alexis-roche/nipy