Avoid change to float window on neovim

[chemzqm]

When there's win_execute() api, coc.nvim won't change to float window, so it's not possible to jump to float window by command like <C-w>w and <C-w>p anymore.

Alternatives for jump to float window:

• Use mouse, requires neovim support mouse.
• :call coc#float#jump()
• :call win_gotoid(g:coc_last_float_win)
• Other custom scripts.