Merge pull request 'add alt text icons' (#775) from fix/add-alt-text-icons into release/v9.1.0

Reviewed-on: https://git.onlyoffice.com/ONLYOFFICE/web-apps/pulls/775

apps/spreadsheeteditor/main/app/view/TableDesignTab.js

@@ -320,7 +320,7 @@ define([
 
                 this.btnAltText = new Common.UI.Button({
                     cls         : 'btn-toolbar x-huge icon-top',
-                    iconCls     : 'toolbar__icon btn-big-pivot-sum',
+                    iconCls     : 'toolbar__icon btn-table-alt-text',
                     caption     : this.txtAltText,
                     lock: [_set.editCell, _set.selRangeEdit, _set.lostConnect, _set.coAuth, _set.wsLock, _set.cantModifyFilter],
                     style       : 'width: 100%;',

apps/spreadsheeteditor/main/resources/img/toolbar/2.5x/big/btn-table-alt-text.svg

@@ -0,0 +1,4 @@
+<svg width="28" height="28" viewBox="0 0 28 28" fill="none" xmlns="http://www.w3.org/2000/svg">
+    <path d="M20.5 20a.5.5 0 0 1 0 1h-4a.5.5 0 0 1 0-1zm0-3a.5.5 0 0 1 0 1h-4a.5.5 0 0 1 0-1z" fill="#000"/>
+    <path d="M21.5 6a.5.5 0 0 1 .5.5V14h1.5a.5.5 0 0 1 .5.5v9a.5.5 0 0 1-.5.5h-10a.5.5 0 0 1-.5-.5V22H4.5a.5.5 0 0 1-.5-.5v-15a.5.5 0 0 1 .5-.5zM14 23h9v-8h-9zm-3-2h2v-6.5a.5.5 0 0 1 .5-.5H21v-2H11zm-6 0h5v-4H5zm0-5h5v-4H5zm0-5h16V7H5z" fill="#000"/>
+</svg>

apps/spreadsheeteditor/main/resources/img/toolbar/v2/2.5x/big/btn-table-alt-text.svg

@@ -0,0 +1,4 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="28" height="28" viewBox="0 0 28 28" stroke="currentColor" stroke-linecap="round" stroke-linejoin="round" fill="none">
+    <path d="M4.5 11.5v-4a1 1 0 0 1 1-1h15a1 1 0 0 1 1 1v4m-17 0h6m-6 0v5m17-5v3m0-3h-11m0 0v5m0 5h-5a1 1 0 0 1-1-1v-4m6 5v-5m0 5h3m-3-5h-6" class="icon-stroke-gray-primary"/>
+    <path d="M20.5 17.5h-4m0 3h4m3 2v-7a1 1 0 0 0-1-1h-8a1 1 0 0 0-1 1v7a1 1 0 0 0 1 1h8a1 1 0 0 0 1-1Z" class="icon-stroke-blue-primary"/>
+</svg>