[GNU ELPA] Smalltalk-Mode version 4.0

[ELPA update]

Version 4.0 of package Smalltalk-Mode has just been released in GNU ELPA.
You can now find it in M-x list-packages RET.

Smalltalk-Mode describes itself as:

  =====================================================
  Major mode for the GNU Smalltalk programming language
  =====================================================

More at https://elpa.gnu.org/packages/smalltalk-mode.html

## Summary:

  Major mode to edit GNU Smalltalk code (https://smalltalk.gnu.org/)
  and interact with an inferior GST interactive session.

## Recent NEWS:

New in 4.0:
- Completely rewritten indentation code, which now relies on SMIE
- Support for `prettify-symbols-mode'
- Use `electric-indent-mode'