(core) hide long sequences of unchanged rows in diffs

Summary:
It can be hard to find changes, even when highlighted, in a table with many rows.  This diff replaces long sequences of unchanged rows with a row containing "..."s.

With daff, I found that it is important to do this for sequences of unchanged columns also, but not tackling that yet.

Test Plan: added test

Reviewers: dsagal

Reviewed By: dsagal

Differential Revision: https://phab.getgrist.com/D2666

app/client/components/BaseView.js

@@ -86,10 +86,10 @@ function BaseView(gristDoc, viewSectionModel, options) {
   }));
 
   // Sorted collection of all rows to show in this view.
-  this.sortedRows = rowset.SortedRowSet.create(this, null);
+  this.sortedRows = rowset.SortedRowSet.create(this, null, this.tableModel.tableData);
 
   // Re-sort when sortSpec changes.
-  this.sortFunc = new SortFunc(new ClientColumnGetters(this.tableModel));
+  this.sortFunc = new SortFunc(new ClientColumnGetters(this.tableModel, {unversioned: true}));
   this.autoDispose(this.viewSection.activeDisplaySortSpec.subscribeInit(function(spec) {
     this.sortFunc.updateSpec(spec);
     this.sortedRows.updateSort((rowId1, rowId2) => {

app/client/components/viewCommon.css

@@ -75,6 +75,11 @@
   background-color: unset;
 }
 
+.field_clip.field-error-S {
+  color: #aaa;
+  background-color: unset;
+}
+
 /* Insert a zero-width space into each cell, to size cells to at least one line of text. */
 .field_clip:empty::before { content: '\200B'; }