add warning from docs about statistics client data potentially being cached

[M-Zuber]

The documentation for the statistics client includes a warning that the data might be cached.
(https://developer.github.com/v3/repos/statistics/#a-word-about-caching)
It might be worthwhile to include that warning or a link to it, in the intellisene on the methods

[hnrkndrssn]

I started looking into this, but had a thought before I did any work on it.

Would it be necessary to have the warning in the intellisense of every method (that's a lot of copy-🍝) or would it be enough to add it just to the intellisense of the class and constructor?

[ryangribble]

Nobody would really be constructing the RepositoryStatisticsClient themselves I dont think, so probably just in the actual class description intellisense would be fine. I also think this would be fine since that paralllels what the official docs do (a single call out at the top, for the whole client) rather than repeating it on each method 👍

[M-Zuber]

That would show up when a user does client.RepositoryStatistics before dotting into an actual method?
If so, then you have my +1