Documentation for integrated_time still specifies discontinued ``axis`` keyword argument

General information:

• emcee version: 3.0.2
• platform: MacOS X
• installation method (pip/conda/source/other?): pip

Problem description:
The docstring for the integrated_time function still mentions the argument 'axis', which does not seem to be implemented anymore. It would be great if the axis argument could be specified, to avoid having to swap axes before passing to this function.

See lines 47 onwards in autocorr.py

    """Estimate the integrated autocorrelation time of a time series.

    This estimate uses the iterative procedure described on page 16 of
    `Sokal's notes <http://www.stat.unc.edu/faculty/cji/Sokal.pdf>`_ to
    determine a reasonable window size.

    Args:
        x: The time series. If multidimensional, set the time axis using the
            ``axis`` keyword argument and the function will be computed for
            every other axis.

Start in autocorr.py at lines 47 onward and inspect the integrated_time entry point, comparing its current signature and behavior with the docstring's axis description. Clarify whether the intended outcome is to remove the obsolete documentation or support axis, then ensure the documentation accurately reflects the resolved behavior.