Remove redundant move in return statement

[Chocobo1]

This suppresses the following warning from gcc 13.2.1:

/home/user/libtorrent-rasterbar-2_0-git/src/libtorrent/bindings/python/src/entry.cpp:23:25: warning: redundant move in return statement [-Wredundant-move]
   23 |         return std::move(result);
      |                ~~~~~~~~~^~~~~~~~

Also refer to the manual:
https://gcc.gnu.org/onlinedocs/gcc-13.2.0/gcc/C_002b_002b-Dialect-Options.html#index-Wredundant-move

[Chocobo1]

It seems clang-10 gives opposite warnings: https://github.com/arvidn/libtorrent/actions/runs/5909524042/job/16030198579?pr=7488#step:8:32 or perhaps clang 10 is simply outdated.

This blog post actually suggest not using std::move in those cases (the paragraph about Wpessimizing-move): https://developers.redhat.com/blog/2019/04/12/understanding-when-not-to-stdmove-in-c
However this might be specific to gcc and clang thinks differently, I'm not sure.

Anyway I'll leave this PR open and let you (arvidn) decide.

[arvidn]

I made this: #7501

[Chocobo1]

Superseded by #7501.