Update lean-toolchain for testing leanprover/lean4#12228

Author: leanprover-community-mathlib4-bot

lake-manifest.json

@@ -65,10 +65,10 @@
    "type": "git",
    "subDir": null,
    "scope": "leanprover-community",
-   "rev": "db33a0238d18dc67cadd81b3fdac53f82b950bb6",
+   "rev": "888eb5791db26096269dc7ea315b5f3b3d66debc",
    "name": "batteries",
    "manifestFile": "lake-manifest.json",
-   "inputRev": "nightly-testing",
+   "inputRev": "lean-pr-testing-12228",
    "inherited": false,
    "configFile": "lakefile.toml"},
   {"url": "https://github.com/leanprover/lean4-cli",

lakefile.lean

@@ -6,7 +6,7 @@ open Lake DSL
 ## Mathlib dependencies on upstream projects
 -/
 
-require "leanprover-community" / "batteries" @ git "nightly-testing"
+require "leanprover-community" / "batteries" @ git "lean-pr-testing-12228"
 require "leanprover-community" / "Qq" @ git "nightly-testing"
 require "leanprover-community" / "aesop" @ git "nightly-testing"
 require "leanprover-community" / "proofwidgets" @ git "v0.0.86" -- ProofWidgets should always be pinned to a specific version

lean-toolchain

@@ -1 +1 @@
-leanprover/lean4:nightly-2026-01-28
+leanprover/lean4-pr-releases:pr-release-12228-bb338a9