create key shortcut in sublime.md

preference -> key binding

write the key shortcut in json file format
the user defined shortcut will override the system shortcut

my defined shortcut

[
    { "keys": ["alt+b"], "command": "show_panel", "args": {"panel": "output.exec"} },
    { "keys": ["alt+0"], "command": "exec", "args": {"kill": true} }
]