emulation: Remove duplicate sequence entry

For commit b38428322ee2c99b9ef5da9208533b817fcf94fe.
emulation: Improve DECSET handler

Use bsearch instead of a linear search.
emulation: Make DECSET handler struct static

By storing just the offsets, we can make the struct static and const.
emulation: Fix function key mode setting

These are boolean values, not pointers!
docs: Add API index for symbols new in 0.36