Update icon readme

icons/README.md

@@ -2,4 +2,12 @@ This icon library is used by the widget
 
 Generated with https://github.com/Nek-12/MaterialSymbolsToFont
 
+```
+Fill? (y/n): n
+Mode? (outlined/rounded/sharp): outlined
+Weight (100-700 by 100):400
+Grade (one of the following: [-25, 0, 200]) :0
+Optical size (one of the following: [20, 24, 40, 48]) :24
+```
+
 Font is split into two classes because it was too big to compile as one