A tiny documentation patch to LLVM Language Reference Manual

OK, I now see how the i32 0 moves inside the struct. But now I have more
questions. According to "The Often Misunderstood GEP Instruction", the
type given to GEP as type of the starting pointer value need not be the
same as the type the value had when it was produced. Yet you say it would
not typecheck as I miscorrected. So, I am guessing the following:

1) In order to change the type in this way, I would need to insert an
    explicit bitcast.

2) Even though I can change the type, it still must be a pointer type
    (I see the language reference says this.) So even with an explicit
    bitcast, my miscorrected example would still fail to typecheck for
    this latter reason.

3) The result of GEP is always a pointer type, the same as the starting
    type if only one index is given, different otherwise.

Am I understanding correctly?