[libc++][ranges][NFC] In the Ranges status, mark move_sentinel as "in…

… progress"

libcxx/docs/Status/RangesPaper.csv

@@ -81,7 +81,7 @@ Section,Description,Dependencies,Assignee,Complete
 | Updates to move_iterator","| [iterator.concepts]
 | [iterator.cust.swap]
 | [iterator.cust.move]",Unassigned,Not started
-`[move.sentinel] <https://wg21.link/move.sentinel>`_,move_sentinel,[predef.iterators],Unassigned,Not started
+`[move.sentinel] <https://wg21.link/move.sentinel>`_,`move_sentinel <https://reviews.llvm.org/D117656>`_,[predef.iterators],Arthur O'Dwyer,In progress
 `[common.iterator] <https://wg21.link/common.iterator>`_,`common_iterator <https://llvm.org/D103335>`_,"| [iterator.concepts]
 | [iterator.cust.swap]
 | [iterator.cust.move]",Zoe Carver,✅