Added new kb article grid-expand-collapse-multilevel-hierarchy#2740

xristianstefanov merged 2 commits intomastertelerik/blazor-docs:masterfrom

new-kb-grid-expand-collapse-multilevel-hierarchy-497031dce66247dd944327c8e21ab5catelerik/blazor-docs:new-kb-grid-expand-collapse-multilevel-hierarchy-497031dce66247dd944327c8e21ab5caCopy head branch name to clipboard