Improve miri's error reporting in check_in_alloc

Author: LooMaclin

src/librustc_mir/interpret/memory.rs

@@ -252,7 +252,8 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> Memory<'a, 'mir, 'tcx, M> {
             Scalar::Ptr(ptr) => {
                 // check this is not NULL -- which we can ensure only if this is in-bounds
                 // of some (potentially dead) allocation.
-                let align = self.check_bounds_ptr(ptr, InboundsCheck::MaybeDead, CheckInAllocMsg::NullPointer)?;
+                let align = self.check_bounds_ptr(ptr, InboundsCheck::MaybeDead,
+                                                  CheckInAllocMsg::NullPointer)?;
                 (ptr.offset.bytes(), align)
             }
             Scalar::Bits { bits, size } => {