[libc++] Document that libc++ does not and will never implement the Networking TS (#127508)

There has been discussion around this a few times already, and there
seemed to be consensus that we would never pursue an implementation of
the Networking TS. This patch solidifies that discussion by documenting
it and closing issues related to the Networking TS.

Closes #103799
Closes #100223
Closes #100228
Closes #100231
Closes #100232

Author: ldionne

libcxx/docs/DesignDocs/ExperimentalFeatures.rst

@@ -160,8 +160,8 @@ has been removed in LLVM 17.0.
 
 `Networking TS <https://wg21.link/N4656>`__
 -------------------------------------------
-The Networking TS is not yet part of a shipping standard.
-We have not yet shipped an implementation of the Networking TS.
+The Networking TS is not yet part of a shipping standard, and there is discussion around removing it.
+Libc++ never shipped an implementation of the Networking TS and does not plan to do so in the future.
 
 `Ranges TS <https://wg21.link/N4685>`__
 ---------------------------------------

libcxx/docs/Status/Cxx20Issues.csv

@@ -13,7 +13,7 @@
 "`LWG2966 <https://wg21.link/LWG2966>`__","Incomplete resolution of US 74","2017-07 (Toronto)","|Nothing To Do|","",""
 "`LWG2974 <https://wg21.link/LWG2974>`__","Diagnose out of bounds ``tuple_element/variant_alternative``\ ","2017-07 (Toronto)","|Complete|","",""
 "","","","","",""
-"`LWG2779 <https://wg21.link/LWG2779>`__","[networking.ts] Relax requirements on buffer sequence iterators","2017-11 (Albuquerque)","","",""
+"`LWG2779 <https://wg21.link/LWG2779>`__","[networking.ts] Relax requirements on buffer sequence iterators","2017-11 (Albuquerque)","|Nothing To Do|","",""
 "`LWG2870 <https://wg21.link/LWG2870>`__","Default value of parameter theta of polar should be dependent","2017-11 (Albuquerque)","|Complete|","",""
 "`LWG2935 <https://wg21.link/LWG2935>`__","What should create_directories do when p already exists but is not a directory?","2017-11 (Albuquerque)","|Nothing To Do|","",""
 "`LWG2941 <https://wg21.link/LWG2941>`__","[thread.req.timing] wording should apply to both member and namespace-level functions","2017-11 (Albuquerque)","|Nothing To Do|","",""
@@ -51,17 +51,17 @@
 "`LWG2975 <https://wg21.link/LWG2975>`__","Missing case for ``pair``\  construction in scoped and polymorphic allocators","2018-03 (Jacksonville)","","",""
 "`LWG2989 <https://wg21.link/LWG2989>`__","``path``\ 's stream insertion operator lets you insert everything under the sun","2018-03 (Jacksonville)","|Complete|","",""
 "`LWG3000 <https://wg21.link/LWG3000>`__","``monotonic_memory_resource::do_is_equal``\  uses ``dynamic_cast``\  unnecessarily","2018-03 (Jacksonville)","|Complete|","16",""
-"`LWG3002 <https://wg21.link/LWG3002>`__","[networking.ts] ``basic_socket_acceptor::is_open()``\  isn't ``noexcept``\ ","2018-03 (Jacksonville)","","",""
+"`LWG3002 <https://wg21.link/LWG3002>`__","[networking.ts] ``basic_socket_acceptor::is_open()``\  isn't ``noexcept``\ ","2018-03 (Jacksonville)","|Nothing To Do|","",""
 "`LWG3004 <https://wg21.link/LWG3004>`__","|sect|\ [string.capacity] and |sect|\ [vector.capacity] should specify time complexity for ``capacity()``\ ","2018-03 (Jacksonville)","|Nothing To Do|","",""
 "`LWG3005 <https://wg21.link/LWG3005>`__","Destruction order of arrays by ``make_shared/allocate_shared``\  only recommended?","2018-03 (Jacksonville)","","",""
 "`LWG3007 <https://wg21.link/LWG3007>`__","``allocate_shared``\  should rebind allocator to *cv*-unqualified ``value_type``\  for construction","2018-03 (Jacksonville)","","",""
 "`LWG3009 <https://wg21.link/LWG3009>`__","Including ``<string_view>``\  doesn't provide ``std::size/empty/data``\ ","2018-03 (Jacksonville)","|Complete|","",""
-"`LWG3010 <https://wg21.link/LWG3010>`__","[networking.ts] ``uses_executor``\  says ""if a type ``T::executor_type``\  exists""","2018-03 (Jacksonville)","","",""
+"`LWG3010 <https://wg21.link/LWG3010>`__","[networking.ts] ``uses_executor``\  says ""if a type ``T::executor_type``\  exists""","2018-03 (Jacksonville)","|Nothing To Do|","",""
 "`LWG3013 <https://wg21.link/LWG3013>`__","``(recursive_)directory_iterator``\  construction and traversal should not be ``noexcept``\ ","2018-03 (Jacksonville)","|Complete|","",""
 "`LWG3014 <https://wg21.link/LWG3014>`__","More ``noexcept``\  issues with filesystem operations","2018-03 (Jacksonville)","|Complete|","",""
 "`LWG3015 <https://wg21.link/LWG3015>`__","``copy_options::*unspecified*``\  underspecified","2018-03 (Jacksonville)","|Nothing To Do|","",""
 "`LWG3017 <https://wg21.link/LWG3017>`__","``list splice``\  functions should use ``addressof``\ ","2018-03 (Jacksonville)","|Complete|","",""
-"`LWG3020 <https://wg21.link/LWG3020>`__","[networking.ts] Remove spurious nested ``value_type``\  buffer sequence requirement","2018-03 (Jacksonville)","","",""
+"`LWG3020 <https://wg21.link/LWG3020>`__","[networking.ts] Remove spurious nested ``value_type``\  buffer sequence requirement","2018-03 (Jacksonville)","|Nothing To Do|","",""
 "`LWG3026 <https://wg21.link/LWG3026>`__","``filesystem::weakly_canonical``\  still defined in terms of ``canonical(p, base)``\ ","2018-03 (Jacksonville)","|Complete|","",""
 "`LWG3030 <https://wg21.link/LWG3030>`__","Who shall meet the requirements of ``try_lock``\ ?","2018-03 (Jacksonville)","|Nothing To Do|","",""
 "`LWG3034 <https://wg21.link/LWG3034>`__","P0767R1 breaks previously-standard-layout types","2018-03 (Jacksonville)","|Complete|","",""