Add note about letter spacing / word spacing

Author: pablosichert

README.md

@@ -55,6 +55,7 @@ Hint: (Generally with React) if you want to preserve newlines from plain text, y
 - Text exceeding horizontal boundaries when "viewport" meta tag is not set accordingly for mobile devices (font boosting leads to wrong calculations). See [issue](https://github.com/One-com/react-truncate/issues/4#issuecomment-226703499)
 - Output in plain text only - no support for markup/HTML. See [issue](https://github.com/One-com/react-truncate/issues/8)
 - Wrong line breaks when custom font is loading after the component has rendered. See [issue](https://github.com/One-com/react-truncate/issues/16)
+- No support for letter spacing / word spacing. See [issue](https://github.com/One-com/react-truncate/issues/59)
 
 ## Integrated example for toggling "read more" text
 ```js