Fix typo in call graph description in change notes

Author: jonjanego

rust/ql/lib/change-notes/released/0.2.4.md

@@ -6,5 +6,5 @@
 * Renamed the `Adt` class to `TypeItem` and moved common predicates from `Struct`, `Enum`, and `Union` to `TypeItem`.
 * Added models for the Axum web application framework.
 * Reading content of a value now carries taint if the value itself is tainted. For instance, if `s` is tainted then `s.field` is also tainted. This generally improves taint flow.
-* The call graph is now more precise for calls that target a trait function with a default implemention. This reduces the number of false positives for data flow queries.
+* The call graph is now more precise for calls that target a trait function with a default implementation. This reduces the number of false positives for data flow queries.
 * Improved type inference for raw pointers (`*const` and `*mut`). This includes type inference for the raw borrow operators (`&raw const` and `&raw mut`) and dereferencing of raw pointers.