c ffi document fixes for c_short.md and c_longlong.md

Author: lygstate

library/core/src/ffi/c_longlong.md

@@ -2,4 +2,4 @@ Equivalent to C's `signed long long` (`long long`) type.
 
 This type will almost always be [`i64`], but may differ on some systems. The C standard technically only requires that this type be a signed integer that is at least 64 bits and at least the size of a [`long`], although in practice, no system would have a `long long` that is not an `i64`, as most systems do not have a standardised [`i128`] type.
 
-[`long`]: c_int
+[`long`]: c_long

library/core/src/ffi/c_short.md

@@ -1,5 +1,3 @@
 Equivalent to C's `signed short` (`short`) type.
 
 This type will almost always be [`i16`], but may differ on some esoteric systems. The C standard technically only requires that this type be a signed integer with at least 16 bits; some systems may define it as `i32`, for example.
-
-[`char`]: c_char