wlr_xcursor_get_resize_name() returns cursor-spec [1] based names
but the default cursor icons shipped in include/xcursor/cursor_data.h
use traditional X cursor names instead.
Compositors that use wlr_xcursor_get_resize_name() to resolve an edge
to a cursor icon name may thus be unable to render appropriate cursor
icons for users that don't have a cursor-spec compliant cursor theme
installed on their system or have it installed in an unusual place.
This patch adds cursor-spec cursor icon name aliases.
[1] https://www.freedesktop.org/wiki/Specifications/cursor-spec/
