During the language/CLI docs reorg, we noticed several pages that were no longer
viable; some were redundant, some useless, and some just very obsolete.
Since we were trying to avoid breaking links at the time, we opted to remove
them from the navs and leave them as "ghost pages" — still accessible, but not
findable.
This commit finally cleans these ghosts up and updates any remaining links to
relevant modern pages. Bustin' makes me feel good. 👻🚫
Rémi Lapeyre