[docs] add section for currently unsupported sql operations#5861

anandbraman merged 3 commits intomainfeldera/feldera:mainfrom

anandraman/fde-29-document-current-limitations-of-feldera-sql-functionsfeldera/feldera:anandraman/fde-29-document-current-limitations-of-feldera-sql-functionsCopy head branch name to clipboard