prepend_unichar
Description:
Converts a Unicode character into UTF-8, and prepends it to the string.
Example: Prepend a unichar:
public static int main (string[] args) {
	// Output: ``喂, world!``
	StringBuilder builder = new StringBuilder (", world!\n");
	builder.prepend_unichar ('喂');
	print (builder.str);
	return 0;
}
    
    valac --pkg glib-2.0 GLib.StringBuilder.prepend_unichar.vala
    Parameters:
| this | |
| wc | 
           a Unicode character  | 
      
Returns:
| 
           this  |