feat: allow bindings for popup-smart-tab

[Sneethe]

A new zstyle; popup-smart-tab-bindings

This can be used to change what keybinds are "reversed" when tmux-popup shows above the cursor.

Examples

zstyle ':fzf-tab:*' fzf-bindings 'tab:toggle+down' 'btab:toggle+up'
zstyle ':fzf-tab:*' popup-smart-tab-bindings 'tab:toggle+up' 'btab:toggle+down'

Or

zstyle ':fzf-tab:*'fzf-bindings 'ctrl-g:top'
zstyle ':fzf-tab:*' popup-smart-tab-bindings 'ctrl-g:top+down'

Fixes:

• [BUG] 在最新版本的 fzf-tab 中无法使用 fzf-bindings 参数绑定 tab:accept #383
• [BUG] fzf-bindings 'tab:accept' stops working after changing directories and going back #390
• feat: swap tab and btab direction when tmux-popup shows above the cursor #326 (comment)