Use onStartupFinished to replace * in activationEvents

[舰队的偶像-岛风酱!]

see document Activation Events | Visual Studio Code Extension API

onStartupFinished

This activation event is emitted and interested extensions will be activated some time after VS Code starts up. This is similar to the * activation event, but it will not slow down VS Code startup. Currently, this event is emitted after all the * activated extensions have finished activating.

...
"activationEvents": [
    "onStartupFinished"
]
...

vscode-file-nesting-config/extension/package.json

Lines 59 to 61 in 93659d4

 "activationEvents": [ 
   "*" 
 ], 

[Anthony Fu]

PR welcome!