Update src/const-safety.md

Co-authored-by: Ralf Jung <post@ralfj.de>

src/const-safety.md

@@ -43,7 +43,7 @@ it requires knowing the actual integer address of `S`.
 
 The way miri handles this is by treating pointer and integer values separately.
 The most primitive kind of value in miri is a `Scalar`, and a scalar is *either*
-a pointer (`Scalar::Ptr`) or a bunch of bits representing an integer
+a pointer (`Scalar::Ptr`) *or* a bunch of bits representing an integer
 (`Scalar::Bits`).  Every value of a variable of primitive type is stored as a
 `Scalar`.  In the code above, casting the pointer `&S` to `*const i32` and then
 to `usize` does not actually change the value -- we end up with a local variable