When using CJK text as the preview title, the display is misplaced

[yetist]

Here's the test code:

#!/usr/bin/env python3

import os
from simple_term_menu import TerminalMenu

def list_files(directory="."):
    return (file for file in os.listdir(directory) if os.path.isfile(os.path.join(directory, file)))

def main():
    terminal_menu = TerminalMenu(list_files(), preview_title="预览",  preview_command="cat {}", preview_size=0.75)
    menu_entry_index = terminal_menu.show()

if __name__ == "__main__":
    main()

The display effect:

[IngoMeyer441]

Thanks again for your fix in #80. :smiley: