Document MSRV for newer bumpalo

Author: Wilfred

Cargo.toml

@@ -53,7 +53,7 @@ wu-diff = "0.1.2"
 # rayon 1.7 requires rust 1.59
 rayon = "1.6.1"
 tree_magic_mini = "3.0.2"
-# bumpalo 3.12 requires newer rust
+# bumpalo 3.12 requires rust 1.60
 bumpalo = "3.11.1"
 unicode-width = "0.1.9"
 crossterm = { version = "0.26.1", features = [] }