v4.0.0-m4

This is the fourth milestone release of Lean 4. It contains many improvements and many new features. For a summary of all new features, see our release notes. We had more than 600 commits since the last milestone.

Contributors:

$ git shortlog -s -n v4.0.0-m3..v4.0.0-m4
   501  Leonardo de Moura
    65  Sebastian Ullrich
    11  Daniel Fabian
    10  larsk21
     5  Gabriel Ebner
     2  E.W.Ayers
     2  Jonathan Coates
     2  Joscha
     2  Mario Carneiro
     2  ammkrn
     1  Chris Lovett
     1  François G. Dorais
     1  Jakob von Raumer
     1  Lars
     1  Patrick Stevens
     1  Wojciech Nawrocki
     1  Xubai Wang
     1  casavaca
     1  zygi