RStyle(style:Str, content:RichText...):RichText
Attaches a new style to a rich text string. Concatenates all content parameters, and returns a new rich text string with the specified attribute added.
RStyle("red", "This is ", RStyle("bold", "great"))produces "This is great".
If any argument is EMPTY, returns EMPTY.
In text mode, this function just returns the concatenation of the content, as rich text attributes have no meaning to the text mode applications.
TODO: document the styles
Since: PCC2 1.99.21
