Responsive design

[sebastianv89]

The website becomes illegible in parts when the screen is too narrow.

The following screenshot of https://neovim.io/doc/user/ demonstrates this.

As you can see the right-hand side menu intersects with the main text.
Also the anchor label (standard-plugin-list in the screenshot) intersects with the text.

(I typically split my 1920 pixel wide monitor in two, which is why this 960px wide screenshot is my default view.)

[justinmk]

The old vim help is hardwrapped. Nvim-owned help pages are softwrapped and have "flow" layout, see https://neovim.io/doc/user/lua.html for example.

I am incrementally migrating more and more pages to "flow" layout, but meanwhile any help with the CSS is welcome. (But please check the results carefully; we've had several half-baked attempts already.)

Meanwhile this is tracked in neovim/neovim.github.io#288