Update mod.rs

This typo looks unnecessary

core/src/mem/mod.rs

@@ -612,7 +612,7 @@ pub const fn needs_drop<T: ?Sized>() -> bool {
 ///
 /// There is no guarantee that an all-zero byte-pattern represents a valid value
 /// of some type `T`. For example, the all-zero byte-pattern is not a valid value
-/// for reference types (`&T`, `&mut T`) and functions pointers. Using `zeroed`
+/// for reference types (`&T`, `&mut T`) and function pointers. Using `zeroed`
 /// on such types causes immediate [undefined behavior][ub] because [the Rust
 /// compiler assumes][inv] that there always is a valid value in a variable it
 /// considers initialized.