Incorrect completion_callback usage example

[ArturGulik]

The documentation here provides the following example of defining the completion_callback argument:

local function my_completion_cb(command_before_comp, cur_pos_before_comp, ncomp)
    return command_before_comp.."foo", cur_pos_before_comp+3, 1
end

This example is not working. The length operator is used on the third output of the callback, here: prompt.lua:840. This suggests that the third output argument should be an array.

If I'm right the example should rather look like this:

local function my_completion_cb(command_before_comp, cur_pos_before_comp, ncomp)
    local completion = command_before_comp.."foo"
    return completion, cur_pos_before_comp+3, {completion}
end