Define command in `devdocs-browser-eww-mode` akin to `devdocs-lookup`.

[krisbalintona]

Hello,

It would be quite convenient to have a command in the EWW browsers that devdocs-browser opens that lets one go to another Devdocs "node" for the current language. For me, this would make Devdocs feel much more Info manual like.

[blahgeek]

In a devdocs-browser buffer, devdocs-browser-open should automatically use current document. Is that what you want?

[krisbalintona]

I see. I think, then, that should be bound to i in devdocs-browser-eww-mode-map. Do you agree?

[krisbalintona]

FYI I have this and a few other features/additions in mind. I'll create issues for them but if you want me to write PRs for them that you can review and merge feel free to let me know.