Heap length is end - start

[thejpster]

The linked list allocator crate defines the heap as [start, start + size)

fn init() calculates size as end - start - 1, which means the heap is [start, end - 1), or one byte shorter than it need be. Size should just be end - start. That's a bug on my part (but at least it's a safe bug).

The comments say the heap size is end - start + 1, which is also wrong. That would mean we included the end byte.