`layout`: Delete outdated comments about ElementType alias not being used because of MSVC

Code below those comments does use ElementType.

PiperOrigin-RevId: 617854731
Change-Id: I7996b8cbaa2fb65855a801f634a57d821408b1f3

absl/container/internal/layout.h

@@ -542,9 +542,6 @@ class LayoutImpl<
   //   std::tie(ints, doubles) = x.Pointers(p);
   //
   // Requires: `p` is aligned to `Alignment()`.
-  //
-  // Note: We're not using ElementType alias here because it does not compile
-  // under MSVC.
   template <class Char>
   auto Pointers(Char* p) const {
     return std::tuple<CopyConst<Char, ElementType<OffsetSeq>>*...>(
@@ -599,9 +596,6 @@ class LayoutImpl<
   //
   // Requires: `p` is aligned to `Alignment()`.
   //
-  // Note: We're not using ElementType alias here because it does not compile
-  // under MSVC.
-  //
   // Note: We mark the parameter as unused because GCC detects it is not used
   // when `SizeSeq` is empty [-Werror=unused-but-set-parameter].
   template <class Char>