[networking.ts] Remove spurious nested value_type buffer sequence requirement

Submitter: Vinnie Falco

The post-condition requirements for ConstBufferSequence and MutableBufferSequence refer to X::value_type, but no such nested type is required. The lambda expression passed to equal can use auto const& parameter types instead.

Proposed resolution:

This wording is relative to N4695.

1. Modify 16.2.1 [buffer.reqmts.mutablebuffersequence], table 12 as indicated:

   [](const typename X::value_type& v1, const typename X::value_type& v2)

   [](const auto& v1, const auto& v2)

2. Modify 16.2.2 [buffer.reqmts.constbuffersequence], table 13 as indicated:

   [](const typename X::value_type& v1, const typename X::value_type& v2)

   [](const auto& v1, const auto& v2)