Fixed SideHistogramPlot xlabel
Fixed SideHistogramPlot xlabel

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