shells/yash: update to yash-2.55

# Changes
Yash 2.55 (2023-08-20)

  +  [line-editing] The Enter/Send key ("\et") now has a default
    binding to the command the Ctrl-M key ("\^M") is bound to in each
    mode.
  =  [line-editing] The redraw-all and clear-and-redraw-all commands
    now can be used with an argument to swap their behavior.
  *  Fixed mistranslation in the Japanese language support.
  .  Updated the sample initialization script (yashrc):
    +  Code example for binding Ctrl-L to clear-and-redraw-all.
  .  Updated completion scripts:
    +  Completion for git-switch and pass

(vins)