title: plotly heatmap in R - change scale title
body: <p>I've created a heat map in R using <code>plot_ly</code>, but I can't for the life of me figure out how to change the name that appears above the colour legend (short of changing the name of the input dataframe).</p>
  
  <p>Trouble is, I'd like spaces in the name of the title, which passing as the data to the <code>plotly</code> call makes difficult.</p>
  
  <p>There MUST be a way to edit it directly as there is for every other label/title surely?!</p>
  
  <p>I was hoping it would inherit from <code>legend=</code> but seemingly no.. Code and output image below (trying to change the bit that currently says "data.matrix, adjwallace").</p>
  
  <p>(I havent provided the data, since it isn't relevant to the particular problem I don't think - and I had to mess with it's format, but I can edit if necessary).</p>
  
  <pre><code>fonts &lt;- list(
  family = "sans-serif",
  size = 12
  )
  
  x.axisSettings &lt;- list(
   title = "",
   zeroline = FALSE,
   showline = FALSE,
   showticklabels = TRUE,
   showgrid = FALSE,
  )
  
  y.axisSettings &lt;- list(
    title = "",
    zeroline = FALSE,
    showline = FALSE,
    showticklabels = TRUE,
    showgrid = FALSE,
  )
  
  legend.Settings &lt;- list(
    font = fonts,
    title = "Adjusted Wallace Coefficients"
  )
  
  plot_ly(z = data.matrix(adjwallace),
          colorscale= "Hot",
          name = "Adjusted Wallace Coefficients",
          x = names(adjwallace),
          y = names(adjwallace),
          type = "heatmap") %&gt;%
    layout(xaxis=x.axisSettings,
           yaxis=y.axisSettings,
           legend=legend.Settings)
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/3sOhJ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/3sOhJ.png" alt="enter image description here"></a></p>