Mac 键盘符号说明
⌘ == Command
⇧ == Shift
⇪ == Caps Lock
⌥ == Option
⌃ == Control
↩ == Return/Enter
⌫ == Delete
⌦ == 向前删除键（Fn+Delete）
↑ == 上箭头
↓ == 下箭头
← == 左箭头
→ == 右箭头
⇞ == Page Up（Fn+↑）
⇟ == Page Down（Fn+↓）
Home == Fn + ←
End == Fn + →
⇥ == 右制表符（Tab键）
⇤ == 左制表符（Shift+Tab）
⎋ == Escape (Esc)
⏏ == 电源开关键
