Improved Overlay label docstring
Improved Overlay label docstring

basnijholt/holoviews,vascotenner/holoviews,basnijholt/holoviews,ioam/holoviews,mjabri/holoviews,mjabri/holoviews,ioam/holoviews,ioam/holoviews,mjabri/holoviews,vascotenner/holoviews,vascotenner/holoviews,basnijholt/holoviews