Add usage documentation about maximum lag and retries

[Xymph]

In all the work and discussion regarding #112, I took a shortcut in not documenting the feature, and my trusty reviewer didn't remind me about it either. 😉

The text already uses WikimateException which doesn't exist yet, but will be defined in my next PR (after this and #133 are merged).

[waldyrious]

LGTM :) I'll wait until this is rebased to merge it.

[waldyrious]

(I do have to mention that I feel a little uneasy with the time-traveling aspect of an earlier commit mentioning a concept that will be introduced in a later commit, but hey, nothing wrong with leaving a little mystery to the future code archeologists :P)

[Xymph]

(I do have to mention that I feel a little uneasy with the time-traveling aspect of an earlier commit mentioning a concept that will be introduced in a later commit, but hey, nothing wrong with leaving a little mystery to the future code archeologists :P)

No offense intended, but would you have felt equally uneasy if I hadn't pointed it out explicitly?
Anyway, thanks for working with me, even into the future. 😉

[waldyrious]

No offense intended, but would you have felt equally uneasy if I hadn't pointed it out explicitly?

Good question! I would likely not have noticed it — or rather, I'd assume it already existed in the codebase, which I don't know nearly as intimately as you do 🙂.