google the title content always led me to something regarding the context menu in the file management of the operating system, or the sublime sidebar. These are not what I want.
I remember once I was able to bind a keyboard shortcut to a sublime’s command that will show the contextual menu at the current cursor position. For example, fix the spelling error at the current word. I trusted google that I can find it later if needed, so I did not back it up.
The command that you want is context_menu; for example:
{
"keys": ["ctrl+shift+c"],
"command": "context_menu",
},
as it is normally executed as the result of a mouse action - i.e. right click, you can check the Packages/Default/Default (OS).sublime-mousemap file to find the command, or just turn command logging on and execute the action and look in the console. No need to google or remember anything 
silly me, for future reference, alt+f2 is the default shortcut existed in sublime 3.