[REF] website: remove anchor option on columns

The anchor option was available on column so that you can target a
column which wraps on a new line in mobile... but we decided to remove
the feature as it complexify the UI.

Also fix a small bug: it was not possible to hit "save" when not
changing the anchor name of an element (an error message was displayed
to say it is already used in the page... while it is in fact used by
itself).

Part of https://github.com/odoo/odoo/pull/36515

addons/website/static/src/js/editor/snippets.options.js

@@ -1492,6 +1492,13 @@ options.registry.anchorName = options.Class.extend({
             click: function () {
                 var $input = this.$('.o_input_anchor_name');
                 var anchorName = $input.val().trim().replace(/\s/g, '_');
+                if (self.$target[0].id === anchorName) {
+                    // If the chosen anchor name is already the one used by the
+                    // element, close the dialog and do nothing else
+                    this.close();
+                    return;
+                }
+
                 var isValid = /^[\w-]+$/.test(anchorName);
                 var alreadyExists = isValid && $('#' + anchorName).length > 0;
                 var anchorOK = isValid && !alreadyExists;

addons/website/views/snippets.xml

@@ -1444,7 +1444,7 @@
 
     <!-- Anchor Name -->
     <div data-js="anchorName"
-        data-selector=":not(p).oe_structure > *, :not(p)[data-oe-type=html] > *, .row > div"
+        data-selector=":not(p).oe_structure > *, :not(p)[data-oe-type=html] > *"
         data-exclude=".modal *">
         <we-button data-no-preview="true" data-open-anchor-dialog="">
             <i class="fa fa-fw fa-anchor"/> Link Anchor