github toc

Adds a floating table of contents for GitHub README pages.

Github toc adds a clean, floating table of contents to GitHub README pages so you can navigate long documentation faster. It reads headings from the README article area, shows `h1` and `h2` at the top level, nests `h3` under the nearest `h2`, and lets you jump through the document with GitHub-compatible anchor links. It also supports collapsing individual sections, collapsing or expanding all `h2` submenus, and keeping long README pages easier to scan without leaving the page.