Set cursorlineopt=both in the builtin previewer

[fsouza]

This way, if the user has defined cursorlineopt=number elsewhere, we
override it to behave as intended.

[ibhagwan]

Tysm for this I can already see myself struggling for maybe a couple of hours struggling with an issue why someone can’t see the cursor line, you just saved me those hours :)

[ibhagwan]

Ok, I just tested I can't merge this as is, this option doesn't exist in the 0.5 release, I can only find it in the nightly version, I have to find a way to first check if the option exists before trying to set it will spawn the error:

Error executing vim.schedule lua callback:
...ack/packer/opt/fzf-lua/lua/fzf-lua/previewer/builtin.lua:112: Invalid option name: 'cursorlineopt'

[ibhagwan]

Merged, solved this by using vim.fn.exists(&option) to verify the option exists before setting it.

[fsouza]

@ibhagwan ohhh my bad, I didn't realize this was a 0.6+ thing. Thanks for fixing it!