C++ docs: link not correctly extracted

Analogous to
https://devdocs.io/cpp/iterator/move_iterator/operator-
there is (e.g. linked in https://devdocs.io/cpp/iterator/move_iterator ) an `operator+`:
https://en.cppreference.com/w/cpp/iterator/move_iterator/operator+
but DevDocs fails to recognize it and the link there goes to a bad url:
https://en.cppreference.com/w/cpp/iterator/move_iterator/operator (i.e. missing trailing `+`)

The same issue is present e.g. for `std::reverse_iterator::operator+`, etc.

Reproduce the bad link from the C++ move_iterator documentation and compare it with the operator- link and the cppreference operator+ URL cited in the issue. Trace the documentation link extraction entry point; done means operator+ and analogous std::reverse_iterator::operator+ links retain the trailing plus and no longer point to the truncated URL.

索引モデルが issue の本文から書いたものです。