#988 Add new function docs, performance notes, and doc updates
- Added documentation for new functions: HtmlEncode/Decode, UrlEncode/Decode, to_utf, split_piped_string, first_point, last_point, outer_single_polygon, outer_multi_polygon, join_near_values, triangualize, griddist_maximp, griddist_zonal, griddist_latitude_specific, invertAll, greedy_alloc, matr_mul/inv/var, strongly_connected_components, Mandelbrot, sd, var, impedance_matrix
- Added detailed performance sections to many function/operator docs
- Updated function index and overview pages with new functions and aliases
- Improved .gitignore and _Sidebar.md, added navigation links and tools
- Updated Projects.md with new project references and links
- Rewrote Debugging.md with Visual Studio 2026 instructions and tips
- Added referenced_pages.txt and orphaned/unreferenced page tracking files
- Improved clarity, formatting, and cross-linking throughout documentation
- Fixed typos and updated links and references