Update src/items/functions.md

Co-Authored-By: Mazdak Farrokhzad <twingoow@gmail.com>

Author: gnzlbg

src/items/functions.md

@@ -164,7 +164,7 @@ let fptr: extern "C" fn() -> i32 = new_i32;
 ```
 
 Functions with an ABI that differs from `"Rust"` do not support 
-unwinding in the exact same way that Rust does, unwinding past the end 
+unwinding in the exact same way that Rust does. Therefore, unwinding past the end 
 of functions with such ABIs causes the process to abort. In LLVM, this is
 implemented by executing an illegal instruction.