[libc++][ranges][NFC] Updated status pages with C++26 papers

Author: H-G-Hristov

libcxx/docs/Status/RangesMajorFeatures.csv

@@ -1,4 +1,5 @@
 Standard,Name,Assignee,CL,Status
+C++26,`Vector API for random number generation <https://wg21.link/P1068R10>`_,Unassigned,No patch yet,Not started
 C++23,`ranges::to <https://wg21.link/P1206R7>`_,Konstantin Varlamov,`D142335 <https://reviews.llvm.org/D142335>`_,Complete
 C++23,`Pipe support for user-defined range adaptors <https://wg21.link/P2387R3>`_,"Louis Dionne, Jakub Mazurkiewicz, and Xiaoyang Liu",Various,Complete
 C++23,`Formatting Ranges <https://wg21.link/P2286R8>`_,Mark de Wever,Various,Complete

libcxx/docs/Status/RangesViews.csv

@@ -36,3 +36,7 @@ C++23,`as_const <https://wg21.link/P2278R4>`_,Unassigned,No patch yet,Not starte
 C++23,`as_rvalue <https://wg21.link/P2446R2>`_,Nikolas Klauser,`D137637 <https://llvm.org/D137637>`_,✅
 C++23,`stride <https://wg21.link/P1899R3>`_,Hristo Hristov and Will Hawkins,`D156924 <https://llvm.org/D156924>`_,In Progress
 C++23,`enumerate <https://wg21.link/P2164R9>`_,Hristo Hristov,`D157193 <https://reviews.llvm.org/D157193>`_,In Progress
+,,,,
+,,,,
+,,,,
+C++26,`concat <https://wg21.link/P2542R7>`_,Unassigned,No patch yet,Not started