fix font name

README.md

                 // Application.targetFrameRate = 60; // or higher if you want a smoother scrolling experience.
     
                 // if you want to use your own font or font icons.
-                // use the font family name instead of the file name in FontStyle.fontFamily.
-                // you can get the font family name by clicking the font file and check its Inspector.                 
+                // use the asset name of font (file name without extension) in FontStyle.fontFamily.             
                 // FontManager.instance.addFont(Resources.Load<Font>(path: "path to your font"));                
             }
     

Runtime/ui/painting/txt/font_manager.cs

             font.hideFlags = HideFlags.DontSave & ~HideFlags.DontSaveInBuild;
 
             FontInfo current;
-            var name = font.fontNames[0];
+            var name = font.name;
-            D.assert(current == null || current.font == font, $"font with name {name} already exists, object name={font.name}");
+            D.assert(current == null || current.font == font, $"font with name {name} already exists");
             var fontInfo = new FontInfo(font);
             this._fonts[name] = fontInfo;
         }
-                D.assert(fontInfo.font.fontNames[0] == name);
+                D.assert(fontInfo.font.name == name);
                 return fontInfo;
             }
 
             osFont.material.mainTexture.hideFlags = HideFlags.DontSave;
 
             var newFont = new FontInfo(osFont);
-            this._fonts[osFont.fontNames[0]] = newFont;
+            this._fonts[osFont.name] = newFont;
 
             return newFont;
         }