update market-movers endpoint

[zvictor]

The current endpoint returns not found.
It should be /movers instead of /market-movers.

Also, I don't see why there is a by: "change" option as I could not find any documentation for it.

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Note: I just arrived here and I couldn't make anything work without #11. I highly recommend @117 take a look at it asap.

[zvictor]

To make it clear, using by throws {"message":"unexpected query parameter(s): by"}