fix typo

Author: FrancoGiachetta

src/metadata/libfunc_counter.rs

@@ -3,7 +3,7 @@
 //!
 //! When this feature is used, the compiler will call one main method:
 //!
-//! 1. `count_libfunc`: called before every libfunc execution. This method will handle the counting. Given a the index
+//! 1. `count_libfunc`: called before every libfunc execution. This method will handle the counting. Given the index
 //!    of a libfunc (relative the its declaration order), it accesses the array of counters and updates the counter.
 //!
 //! In the context of Starknet contracts, we need to add support for building the arrays of counters for multiple executions.