Migrate to Fisherman to improve performance?

[ghost]

While it is true that Fisherman will support init events via the OMF plugin, this will be slower than the default Fisherman style.

Basically, remove the init and uninstall event functions. So, what I mean is remove function __fzf_init and leave the code inside just like that in the fzf.fish file. It will be sourced at the beginning of the shell start.

[ghost]

@gretel Ping.