Fix rustChannelOf usage (the argument is sha256, not hash) to fix pure evaluation

Dependencies

• [2] GHO6DWPI Refactoring iterators
• [3] ZWPPIJXF flake.nix: use Mozilla overlay for Rust
• [*] SXEYMYF7 Fixing the bad changes in history (unfortunately, by rebooting).

Change contents

• replacement in flake.nix at line 22
  [2.67675]→[2.67675:67749](∅→∅)
  − hash = "sha256-KCh2UBGtdlBJ/4UOqZlxUtcyefv7MH1neoVNV4z0nWs=";
  [2.67675]

  [3.357]
  + sha256 = "sha256-KCh2UBGtdlBJ/4UOqZlxUtcyefv7MH1neoVNV4z0nWs=";