(core) Polish and enable Reference List widget

Summary:
Adds Reference List as a widget type.

Reference List is similar to Choice List: multiple references can be added
to each cell through a similar editor, and the individual references
will always reflect their current value from the referenced table.

Test Plan: Browser tests.

Reviewers: dsagal

Reviewed By: dsagal

Subscribers: paulfitz, jarek, alexmojaki, dsagal

Differential Revision: https://phab.getgrist.com/D2959

app/common/ColumnFilterFunc.ts

@@ -1,7 +1,7 @@
 import { CellValue } from "app/common/DocActions";
 import { FilterState, makeFilterState } from "app/common/FilterState";
 import { decodeObject } from "app/plugin/objtypes";
-import { isList } from "./gristTypes";
+import { isList, isRefListType } from "./gristTypes";
 
 export type ColumnFilterFunc = (value: CellValue) => boolean;
 
@@ -13,7 +13,7 @@ export function makeFilterFunc({ include, values }: FilterState,
   // For example, a TypeError in the formula column and the string '["E","TypeError"]' would be seen as the same.
   // TODO: This narrow corner case seems acceptable for now, but may be worth revisiting.
   return (val: CellValue) => {
-    if (isList(val) && columnType === 'ChoiceList') {
+    if (isList(val) && (columnType === 'ChoiceList' || isRefListType(String(columnType)))) {
       const list = decodeObject(val) as unknown[];
       return list.some(item => values.has(item as any) === include);
     }

app/common/gristTypes.ts

@@ -329,6 +329,10 @@ export function getReferencedTableId(type: string) {
   return removePrefix(type, "Ref:") || removePrefix(type, "RefList:");
 }
 
-export function isFullReferencingType(type: string) {
-  return type.startsWith('Ref:') || type.startsWith('RefList:');
+export function isRefListType(type: string) {
+  return type.startsWith('RefList:');
+}
+
+export function isFullReferencingType(type: string) {
+  return type.startsWith('Ref:') || isRefListType(type);
 }