[libc++] Acquire locks on Ranges work

[ldionne]

Summary

This commit acquires locks on a few elements of Ranges to make sure we don't
duplicate work. @zoecarver @cjdb please comment here if you want to acquire
locks of your own (or if you want dibs on one of the two features I'm locking)
and I'll add them.

[cjdb]

I'll take ref_view, views::all, and join_view for now.

[zoecarver]

I'll take view.interface and you should also mark range.view as done, I think (unless that's already done and the CI just hasn't re-built the docs).

Thanks!

[ldionne]

Acquire locks for cjdb and zoecarver

libcxx/docs/OneRangesProposalStatus.csv

 [range.view],View and enable_view,[range.range],,,
 [range.refinements],"OutputRange, InputRange, ForwardRange, BidirectionalRange, RandomAccessRange, ContiguousRange, CommonRange, ViewableRange","[ranges.syn]: pt. 2, [range.range]",Christopher Di Bella,"input_range: `D100271 <https://llvm.org/D100271>`_
 forward_range: `D100275 <https://llvm.org/D100275>`_
 bidirectional_range: `D100278 <https://llvm.org/D100278>`_",
 [view.interface],[range.utility.helpers] and view_interface,"[ranges.syn]: pt. 2, [range.view], [range.iterator.operations.prev], [range.refinements]",,,
 [range.subrange],,[view.interface],,,
 [range.all],view::all,"[range.subrange], [range.view.ref]",,,
 [range.view.ref],ref-view,[view.interface],,,
-[range.filter],filter_view,[range.all],,,
+[range.filter],filter_view,[range.all],,Louis Dionne,
 [range.transform],transform_view,[range.all],,,
-[range.iota],iota_view,[range.all],,,
+[range.iota],iota_view,[range.all],,Louis Dionne,
 [range.take],take_view,[range.all],,,
 [range.join],join_view,[range.all],,,
 [range.empty],empty_view,[view.interface],,,
 [range.single],single_view,[view.interface],,,
 [range.split],split_view,[range.all],,,
 [range.counted],view::counted,[range.subrange],,,
 [range.common],common_view,[range.all],,,
 [range.reverse],reverse_view,[range.all],,,