[libc++][NFC] Fixes a status page note and a minor copy & paste error in a test (#90399)

- Adds a status page note for P3142R0
- Fixes a copy & paste error in tuple protocol for `complex`

Author: H-G-Hristov

libcxx/docs/Status/Cxx2c.rst

@@ -40,6 +40,7 @@ Paper Status
 .. note::
 
    .. [#note-P2510R3] This paper is applied as DR against C++20. (MSVC STL and libstdc++ will do the same.)
+   .. [#note-P3142R0] This paper is applied as DR against C++23. (MSVC STL and libstdc++ will do the same.)
 
 .. _issues-status-cxx2c:
 

libcxx/docs/Status/Cxx2cPapers.csv

@@ -51,7 +51,7 @@
 "`P2869R4 <https://wg21.link/P2869R4>`__","LWG","Remove Deprecated ``shared_ptr`` Atomic Access APIs from C++26","Tokyo March 2024","|Complete|","19.0",""
 "`P2872R3 <https://wg21.link/P2872R3>`__","LWG","Remove ``wstring_convert`` From C++26","Tokyo March 2024","|Complete|","19.0",""
 "`P3107R5 <https://wg21.link/P3107R5>`__","LWG","Permit an efficient implementation of ``std::print``","Tokyo March 2024","","","|format| |DR|"
-"`P3142R0 <https://wg21.link/P3142R0>`__","LWG","Printing Blank Lines with ``println``","Tokyo March 2024","|Complete|","19.0","|format|"
+"`P3142R0 <https://wg21.link/P3142R0>`__","LWG","Printing Blank Lines with ``println``","Tokyo March 2024","|Complete| [#note-P3142R0]_","19.0","|format|"
 "`P2845R8 <https://wg21.link/P2845R8>`__","LWG","Formatting of ``std::filesystem::path``","Tokyo March 2024","","","|format|"
 "`P0493R5 <https://wg21.link/P0493R5>`__","LWG","Atomic minimum/maximum","Tokyo March 2024","","",""
 "`P2542R8 <https://wg21.link/P2542R8>`__","LWG","``views::concat``","Tokyo March 2024","","","|ranges|"

libcxx/test/std/numerics/complex.number/complex.tuple/get.pass.cpp

@@ -111,7 +111,7 @@ constexpr void test() {
 
     std::same_as<std::vector<T>> decltype(auto) imags{
         arr | std::views::elements<1> | std::ranges::to<std::vector<T>>()};
-    assert(reals.size() == 2);
+    assert(imags.size() == 2);
     assert(imags[0] == T{28});
     assert(imags[1] == T{94});
   }