VF Blocks: Tree - Add usage guidelines to the documentation

[bhushan-ebi]

The current documentation for the vf-tree component does not provide guidelines on when the component should or should not be used. Add details to the documentation of this component to address this gap.

Examples of documentation for the tree component

• Carbon design system: Tree component

Useful links

• vf-tree
• Component review sheet
• Vf figma library
• Vf-blocks review in figjam
• Slides: Review of vf blocks