Can't change legend heading for layer

[Anonymous User]

This has supposedly been implemented in Pro 1.3 (Change layer legend "heading" in ArcGIS Pro ) but it is still not working for me. I have a raster and set it up my symbology to classify. I need to be able to differentiate my values in the legend. The raster is an image so there is no attribute table. When I select Classify I do not have an option to select Field or Normalization (see image1) which is fine. However, I need to tell the user what the data represents, in this case pounds per acre. I cannot change the name from "Value" to what I want for the legend in the TOC (see image2). Any advice?

I'm using Pro 2.1.3