[IMP] web_editor,website: rename "background image options" option

"Background Image Options" -> "Background Image Sizing"

addons/web_editor/static/src/js/snippets.options.js

@@ -402,7 +402,7 @@ odoo.define('web_editor.snippets.options', function (require) {
             this.bg_siz = self.$target.css('background-size').split(' ');
 
             this.modal = new Dialog(null, {
-                title: _t("Background Image Options"),
+                title: _t("Background Image Sizing"),
                 $content: $(qweb.render('web_editor.dialog.background_position')),
                 buttons: [
                     {text: _t("Ok"), classes: "btn-primary", close: true, click: _.bind(this.save, this)},

addons/website/views/snippets.xml

@@ -735,7 +735,7 @@
     <div data-js='background_position'
         data-selector="section, :not(.o_gallery > .container) > .carousel, .parallax">
         <li class="background_position_li" data-background_position="background_position">
-            <a tabindex="-1" href="#"><i class="fa fa-cog"/>Background Image Options</a>
+            <a tabindex="-1" href="#"><i class="fa fa-cog"/>Background Image Sizing</a>
         </li>
     </div>