Revert "Update link for assistant documentation"
Revert "Update link for assistant documentation"

This reverts commit a4458f8d3f0564ccca4b06117eedd4f7dfbd0f36.

watson-developer-cloud/ios-sdk,watson-developer-cloud/ios-sdk,watson-developer-cloud/ios-sdk,watson-developer-cloud/ios-sdk,watson-developer-cloud/ios-sdk