feature request: keyboard to expand or collapse

[lundeen-bryan]

It doesn't look like VS Code has a way to expand all folders in the explorerFolders view or in NERDTREE, but collapsing can be accomplished by the following keybinding:
{
"key": "shift+alt+-",
"command": "workbench.files.action.collapseExplorerFolders"
}

I wanted to suggest this option natively in NERDTREE as a feature. So a keybinding could either expand or collapse all folders.