`<algorithm>`: `ranges::inplace_merge` accidentally constructed `remove_cvref_t<iter_rvalue_reference_t <I>>`

[hewillk]

This is basically a sibling of #4102.

https://github.com/microsoft/STL/blob/1c59a205787f4fdcd9c20decc8fa6dfa9096d394/stl/inc/algorithm#L7614-L7630

auto _Temp = _RANGES iter_move(_Mid) unexpectedly constructed remove_cvref_t<iter_reference_t<I>>.

Contrived testcase: https://godbolt.org/z/b7YqKPMej

[frederick-vs-ja]

It seems that we should use iter_value_t<_It> _Temp(_RANGES iter_move(_First));.

[StephanTLavavej]

Agreed. As in https://github.com/microsoft/STL/issues/4102#issuecomment-1769421279 this also indicates missing test coverage.