[CALCITE-1796] Update materialized views documentation
[CALCITE-1796] Update materialized views documentation

dindin5258/calcite,looker-open-source/calcite,vlsi/incubator-calcite,b-slim/calcite,vlsi/calcite,dindin5258/calcite,datametica/calcite,julianhyde/calcite,dindin5258/calcite,minji-kim/calcite,vlsi/calcite,xhoong/incubator-calcite,apache/calcite,vlsi/calcite,looker-open-source/calcite,datametica/calcite,arina-ielchiieva/calcite,apache/calcite,apache/calcite,vlsi/calcite,minji-kim/calcite,apache/calcite,julianhyde/calcite,jcamachor/calcite,googleinterns/calcite,datametica/calcite,arina-ielchiieva/calcite,jcamachor/calcite,googleinterns/calcite,minji-kim/calcite,looker-open-source/calcite,b-slim/calcite,dindin5258/calcite,julianhyde/calcite,dindin5258/calcite,datametica/calcite,julianhyde/calcite,vlsi/incubator-calcite,datametica/calcite,b-slim/calcite,xhoong/incubator-calcite,googleinterns/calcite,xhoong/incubator-calcite,looker-open-source/calcite,dindin5258/calcite,arina-ielchiieva/calcite,julianhyde/calcite,googleinterns/calcite,datametica/calcite,arina-ielchiieva/calcite,jcamachor/calcite,vlsi/calcite,looker-open-source/calcite,looker-open-source/calcite,minji-kim/calcite,jcamachor/calcite,googleinterns/calcite,jcamachor/calcite,minji-kim/calcite,julianhyde/calcite,b-slim/calcite,googleinterns/calcite,apache/calcite,b-slim/calcite,jcamachor/calcite,arina-ielchiieva/calcite,vlsi/calcite,apache/calcite,xhoong/incubator-calcite