[FIX] web: correctly display header tooltips in list

A traceback occured when displaying the tooltip (only visible in debug) on a list
view header if the field had a `widget` attribute (introduced in rev. odoo/odoo@5dc971b).

The issue here was linked to the fact that a widget is not always rendered in list view
(compared to form view) so the `Widget` property in the attributes was not there.

Task 1981757

addons/web/static/src/js/views/list/list_renderer.js

@@ -716,7 +716,7 @@ var ListRenderer = BasicRenderer.extend({
                 name: name,
                 string: description || name,
                 record: this.state,
-                attrs: node.attrs,
+                attrs: _.extend({}, node.attrs, this.state.fieldsInfo.list[name]),
             };
             this._addFieldTooltip(fieldDescr, $th);
         } else {

addons/web/static/tests/views/list_tests.js

@@ -1678,7 +1678,7 @@ QUnit.module('Views', {
     });
 
     QUnit.test('display a tooltip on a field', async function (assert) {
-        assert.expect(2);
+        assert.expect(4);
 
         var initialDebugMode = config.debug;
         config.debug = false;
@@ -1687,24 +1687,34 @@ QUnit.module('Views', {
             View: ListView,
             model: 'foo',
             data: this.data,
-            arch: '<tree><field name="foo"/></tree>',
+            arch: '<tree>' +
+                    '<field name="foo"/>' +
+                    '<field name="bar" widget="toggle_button"/>' +
+                '</tree>',
         });
 
         // this is done to force the tooltip to show immediately instead of waiting
         // 1000 ms. not totally academic, but a short test suite is easier to sell :(
-        list.$('th:not(.o_list_record_selector)').tooltip('show', false);
+        list.$('th[data-name=foo]').tooltip('show', false);
 
-        list.$('th:not(.o_list_record_selector)').trigger($.Event('mouseenter'));
+        list.$('th[data-name=foo]').trigger($.Event('mouseenter'));
         assert.strictEqual($('.tooltip .oe_tooltip_string').length, 0, "should not have rendered a tooltip");
 
         config.debug = true;
         // it is necessary to rerender the list so tooltips can be properly created
         await list.reload();
-        list.$('th:not(.o_list_record_selector)').tooltip('show', false);
-
-        list.$('th:not(.o_list_record_selector)').trigger($.Event('mouseenter'));
+        list.$('th[data-name=foo]').tooltip('show', false);
+        list.$('th[data-name=foo]').trigger($.Event('mouseenter'));
         assert.strictEqual($('.tooltip .oe_tooltip_string').length, 1, "should have rendered a tooltip");
 
+        await list.reload();
+        list.$('th[data-name=bar]').tooltip('show', false);
+        list.$('th[data-name=bar]').trigger($.Event('mouseenter'));
+        assert.containsOnce($, '.oe_tooltip_technical>li[data-item="widget"]',
+            'widget should be present for this field');
+        assert.strictEqual($('.oe_tooltip_technical>li[data-item="widget"]')[0].lastChild.wholeText.trim(),
+            'Button (toggle_button)', "widget description should be correct");
+
         config.debug = initialDebugMode;
         list.destroy();
     });