Feature Request: Add Hierarchical Lines to Expandable Row RC Table

I propose adding hierarchical lines to the expandable row feature of the rc-table component. These lines would visually connect parent rows with their child rows, enhancing usability and clarity for users navigating hierarchical data sets. The implementation should dynamically adjust lines based on row expand/collapse state and include customization options for line style, color, and thickness. Integrating hierarchical lines will provide consistency with other components like rc-tree and improve the interpretation of hierarchical data within the table.

Attached to this issue are screenshots illustrating the desired placement and appearance of the hierarchical lines within the rc-table component. These visuals serve to clarify the requested feature and provide guidance for implementation.

Start by reading the rc-table expandable row feature and comparing its hierarchy presentation with rc-tree. Use the attached screenshots to clarify the intended placement and appearance of the connecting lines. Done means lines respond to row expansion and collapse and expose customization for style, color, and thickness.