(docs) dead link for "middle button emulation"

[sodiboo]

the documentation for the input::Device::config_middle_emulation_* methods contain a link "middle button emulation" which points to a 404 page, which in turn points me to the new location of the page

https://docs.rs/input/0.8.3/input/struct.Device.html#method.config_middle_emulation_default_enabled

dead link (current): https://wayland.freedesktop.org/libinput/doc/latest/middle_button_emulation.html
new link: https://wayland.freedesktop.org/libinput/doc/latest/middle-button-emulation.html