[Lexer] Operators need space before writing the next token

[wesuRage]

the code bellow throws an lexer error:

extern int writeln(string) ; 
extern string strrep(string, int) ; 

def main() -> int: 
  writeln("oi" * 20);

  return 0; 
end; 

It's needed to write it like this for it to work:

extern int writeln( string) ; 
extern string strrep( string, int) ; 

def main( ) -> int: 
  writeln( "oi" * 20 ) ;

  return 0; 
end;