What does this mean?
Well, basically, whenever you hover your mouse cursor over a function or variable in LDT, a small window will pop up displaying any comments located above or in-line-with the function or variable. However, you can take it a step further: if you format your function comments in the LuaDoc syntax, you can enter descriptions of what the function does, what each parameter does, any return values, etc. Here's what LuaDoc looks like in action with a custom function:
Function declaration in normal .lua file:
Here's what it looks like in action with a pre-defined LuaDoc library:
Function declaration in .doclua file: