update markdown version of sharding docs to indicate keys can be > 1 byte
update markdown version of sharding docs to indicate keys can be > 1 byte

HubSpot/vitess,applift/vitess,alainjobart/vitess,mahak/vitess,pivanof/vitess,applift/vitess,applift/vitess,mattharden/vitess,vitessio/vitess,alainjobart/vitess,mattharden/vitess,davygeek/vitess,tirsen/vitess,sougou/vitess,HubSpot/vitess,davygeek/vitess,dcadevil/vitess,vitessio/vitess,vitessio/vitess,tinyspeck/vitess,vitessio/vitess,sougou/vitess,tinyspeck/vitess,tirsen/vitess,pivanof/vitess,dcadevil/vitess,dcadevil/vitess,pivanof/vitess,tinyspeck/vitess,sougou/vitess,alainjobart/vitess,mahak/vitess,davygeek/vitess,tirsen/vitess,enisoc/vitess,tirsen/vitess,rnavarro/vitess,mattharden/vitess,mahak/vitess,alainjobart/vitess,mattharden/vitess,rnavarro/vitess,mattharden/vitess,applift/vitess,enisoc/vitess,applift/vitess,vitessio/vitess,sougou/vitess,sougou/vitess,mattharden/vitess,rnavarro/vitess,davygeek/vitess,applift/vitess,applift/vitess,mahak/vitess,rnavarro/vitess,alainjobart/vitess,dcadevil/vitess,mattharden/vitess,HubSpot/vitess,alainjobart/vitess,pivanof/vitess,applift/vitess,mahak/vitess,enisoc/vitess,enisoc/vitess,applift/vitess,davygeek/vitess,alainjobart/vitess,tinyspeck/vitess,enisoc/vitess,mattharden/vitess,tinyspeck/vitess,mahak/vitess,dcadevil/vitess,rnavarro/vitess,mahak/vitess,HubSpot/vitess,tirsen/vitess,HubSpot/vitess,davygeek/vitess,alainjobart/vitess,rnavarro/vitess,tirsen/vitess,HubSpot/vitess,mahak/vitess,tirsen/vitess,mattharden/vitess,HubSpot/vitess,pivanof/vitess,HubSpot/vitess,enisoc/vitess,applift/vitess,tirsen/vitess,sougou/vitess,vitessio/vitess,vitessio/vitess,dcadevil/vitess,rnavarro/vitess,davygeek/vitess,pivanof/vitess,mattharden/vitess,tinyspeck/vitess,tinyspeck/vitess,pivanof/vitess,dcadevil/vitess,pivanof/vitess,pivanof/vitess,vitessio/vitess,rnavarro/vitess,rnavarro/vitess,enisoc/vitess,sougou/vitess,tirsen/vitess,sougou/vitess