update document

#' This functions can be used to visualize simply and directly a correlation matrix.

#' @param data one of 'correlate', 'rcorr' or 'corr.test' object.

#' @param mapping default list of aesthetic mappings to use for plot.

#' @param drop logical.

#' @param drop logical, if TRUE will drop unused axis labels.

#' @param grid_col colour of panel grid.

#' @param grid_size size of panel grid.

#' @param fixed if TRUE (default), will add \code{coord_fixed()} to plot.

\item{mapping}{default list of aesthetic mappings to use for plot.}

\item{drop}{logical.}

\item{drop}{logical, if TRUE will drop unused axis labels.}

\item{grid_col}{colour of panel grid.}