[libc++] Mark P2017R1 as complete (#74484)

[P2017R1](https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/p2017r1.html#wording)
appears to have been implemented in LLVM 16.0:
https://godbolt.org/z/GbcT4rjcd.

Author: JMazurkiewicz

libcxx/docs/Status/Cxx23Papers.csv

@@ -5,7 +5,7 @@
 "`P1679R3 <https://wg21.link/P1679R3>`__","LWG","string contains function","Autumn 2020","|Complete|","12.0"
 "","","","","","",""
 "`P1682R3 <https://wg21.link/P1682R3>`__","LWG","std::to_underlying for enumerations","February 2021","|Complete|","13.0"
-"`P2017R1 <https://wg21.link/P2017R1>`__","LWG","Conditionally borrowed ranges","February 2021","","","|ranges|"
+"`P2017R1 <https://wg21.link/P2017R1>`__","LWG","Conditionally borrowed ranges","February 2021","|Complete|","16.0","|ranges|"
 "`P2160R1 <https://wg21.link/P2160R1>`__","LWG","Locks lock lockables","February 2021","",""
 "`P2162R2 <https://wg21.link/P2162R2>`__","LWG","Inheriting from std::variant","February 2021","|Complete|","13.0"
 "`P2212R2 <https://wg21.link/P2212R2>`__","LWG","Relax Requirements for time_point::clock","February 2021","",""