SheetAI App Updates - New Function, Easy to choose Model and more.

- Created new function RANGESTRING to get range as string - Updated maxwords to responsetoken in SHEETAI function - Model can be provided as single letter word or full, so there are multiple models davinci, curie, babbage, ada source. By default it&text-davinci-003, you can others like this =SHEETAI("your prompt",40,0.4,"b") for babbage - added /help section providing information on problem you might face - added link to live chat #artificialintelligence