chore: update toolchain nightly-2026-05-21

fgdorais · fgdorais · commit d81ccf95108d · 2026-05-21T10:16:23.000Z
diff --git a/lean-toolchain b/lean-toolchain
@@ -1 +1 @@
-leanprover/lean4:nightly-2026-05-18
+leanprover/lean4:nightly-2026-05-21
