LÖVE

Aha, so this is where the version/platform might matter. This is how it looks for me:

Löve's docset works fine, however. Well, at least now I know that Lua's docset actually works too, and the problem is on my end.

I only tried Lua 5.2

I tired all three (5.1, 5.2, 5.3), they all behave the same. However, the solution turned out to be simple: I upgraded to the currently latest unstable build.