[out.ptr.t][inout.ptr.t] Get rid of TBAA-violating implication

On many platforms, we can just reuse the object/value representation of
the raw pointer stored within `(in)out_ptr_t` for `operator void**`.
However, directly use of `reinterpret_cast` violates the strict aliasing
rule ([basic.lval]/11). At the time when `out_ptr_t` and `inout_ptr_t`
were added to C++23, there was not yet any standard utility bypassing
the strict aliasing rule, and thus the notes had to indicate core UB and
were only applicable for implementations that didn't aggressively
perform type-based aliasing analysis (TBAA).

Luckily, `start_lifetime_as` was added later, making it possible to
reuse value representation without UB. This PR uses `start_lifetime_as`
in the notes, and thus makes them probably applicable for
implementations that have compatible representations for `T*` and
`void*`.

Note that `start_lifetime_as` can cause conflicts on object creation,
but conflicts are already allowed in [out.ptr.t]/5 and [inout.ptr.t]/5.

Author: frederick-vs-ja

source/memory.tex

@@ -5509,7 +5509,7 @@
 
 \pnum
 \begin{note}
-\tcode{reinterpret_cast<void**>(static_cast<Pointer*>(*this))}
+\tcode{start_lifetime_as<void*>(\&const_cast<Pointer\&>(p))}
 can be a viable implementation strategy for some implementations.
 \end{note}
 \end{itemdescr}
@@ -5745,7 +5745,7 @@
 
 \pnum
 \begin{note}
-\tcode{reinterpret_cast<void**>(static_cast<Pointer*>(*this))}
+\tcode{start_lifetime_as<void*>(\&const_cast<Pointer\&>(p))}
 can be a viable implementation strategy for some implementations.
 \end{note}
 \end{itemdescr}