Fix typo

Cargo.toml

@@ -31,7 +31,7 @@ borsh = ["dep:borsh"]
 
 schemars = ["dep:schemars", "std"]
 
-# Provide a soundness promixe to the compiler that the unerlying value is always within range
+# Provide a soundness promise to the compiler that the underlying value is always within range.
 # This optimizes e.g. indexing range checks when passed in an API.
 # The downside of this feature is that it involves an unsafe call to `core::hint::assert_unchecked` during `value()`.
 hint = []