Nushell Documentation Updates

- hustcer created [Add nav links for some new de docs, and do dome doc formatting](https://github.com/nushell/nushell.github.io/pull/495), and [Fix side nav links for nu book](https://github.com/nushell/nushell.github.io/pull/491), and [Fix some broken links](https://github.com/nushell/nushell.github.io/pull/490), and [fix: update deploy workflow for checkout](https://github.com/nushell/nushell.github.io/pull/487), and [Revert "Fix checkout step for feed plugin"](https://github.com/nushell/nushell.github.io/pull/486), and [Fix checkout step for feed plugin](https://github.com/nushell/nushell.github.io/pull/485), and [fix feed plugin configs, make it work as expected](https://github.com/nushell/nushell.github.io/pull/484), and [feat: Add sitemap generator to create sitemap.xml](https://github.com/nushell/nushell.github.io/pull/483), and [Fix responsive layout for more screen size](https://github.com/nushell/nushell.github.io/pull/482), and [Fix responsive layout for mobile devices](https://github.com/nushell/nushell.github.io/pull/480), and [Update prettier config and run code format](https://github.com/nushell/nushell.github.io/pull/479), and [fix feed plugin add atom support](https://github.com/nushell/nushell.github.io/pull/478), and [Fix search box style, make it wider](https://github.com/nushell/nushell.github.io/pull/477), and [Fix search box style, make it align left](https://github.com/nushell/nushell.github.io/pull/476), and [Trigger deploy workflow](https://github.com/nushell/nushell.github.io/pull/475), and [Fix command detail page, update make_docs.nu](https://github.com/nushell/nushell.github.io/pull/474), and [Upgrade vuepress to v2 and add dark mode support](https://github.com/nushell/nushell.github.io/pull/465) - petrisch created [Some new German translation with new snippet links](https://github.com/nushell/nushell.github.io/pull/494) - elferherrera created [remove dfr from dataframe chapter](https://github.com/nushell/nushell.github.io/pull/493), and [lazyframes section](https://github.com/nushell/nushell.github.io/pull/466) - lfritz created [Fix a couple of typos](https://github.com/nushell/nushell.github.io/pull/492) - CAD97 created [Replace `str find-replace` with `str replace` in `coming_from_bash.md`](https://github.com/nushell/nushell.github.io/pull/489) - sec65 created [Add doc for loginshell file #4620](https://github.com/nushell/nushell.github.io/pull/488) - Dan-Gamin created [Add more documentation about strings](https://github.com/nushell/nushell.github.io/pull/481) - merelymyself created [Add documentation for switch flags](https://github.com/nushell/nushell.github.io/pull/471) - fdncred created [remove file paths since they're not a thing any longer](https://github.com/nushell/nushell.github.io/pull/470) - jgollenz created [Add 'Reading environment variables' section](https://github.com/nushell/nushell.github.io/pull/469), and [typos](https://github.com/nushell/nushell.github.io/pull/462) - Yethal created [Update dataframes.md](https://github.com/nushell/nushell.github.io/pull/467)

This section details documentation updates. hustcer: Nav links for DE docs, formatting, link fixes, workflow updates, sitemap, layout fixes, Prettier config, Atom support, search box fixes, deploy trigger, command detail page fix, Vuepress v2/dark mode. petrisch: German translations. elferherrera: DataFrame chapter updates. lfritz: Typo fixes. CAD97: Replaced `str find-replace` with `str replace`. sec65: Login shell doc. Dan-Gamin: String documentation. merelymyself: Switch flag documentation. fdncred: Removed file paths. jgollenz: Added environment variables section, typo fixes. Yethal: DataFrame updates.