Issue #3405021 by pdureau: Align expected variables and variables used in templates

templates/patterns/alert/pattern-alert.html.twig

-{% if variant and variant|lower != 'default' %}
-  {% set attributes = attributes.addClass('alert-' ~ variant|lower|replace({'_': '-'})) %}
+{% if variant and variant != 'default' %}
+  {% set attributes = attributes.addClass('alert-' ~ variant) %}
 {% endif %}
 
 {% if dismissible %}
   {% set attributes = attributes.addClass(['alert-dismissible', 'fade', 'show']) %}
 {% endif %}
 
-<div{{ attributes.addClass('alert').setAttribute('role', alert) }}>
+<div{{ attributes.addClass('alert').setAttribute('role', 'alert') }}>
   {% if heading %}
   <h4 class="alert-heading">{{ heading }}</h4>
   {% endif %}

templates/patterns/blockquote/blockquote.ui_patterns.yml

 blockquote:
   label: "Blockquote"
   description: "For quoting blocks of content from another source within your document. https://getbootstrap.com/docs/4.6/content/typography/#blockquotes"
-  variants:
-    default:
-      label: Default
-    fluid:
-      label: Fluid
-      description: This is a modified jumbotron that occupies the entire horizontal space of its parent, and without rounded corners.
   fields:
     content:
       type: "render"

templates/patterns/dropdown/pattern-dropdown.html.twig

 {% set attributes = direction ? attributes.addClass('drop' ~ direction) : attributes.addClass('dropdown') %}
-{% set attributes = split ? attributes.addClass('btn-group') : attributes %}
+{% set attributes = button_url ? attributes.addClass('btn-group') : attributes %}
 
 <div{{ attributes }}>
   {% if button_url %}

templates/patterns/figure/pattern-figure.html.twig

-{% if variant and variant|lower != 'default' %}
-  {% set attributes = attributes.addClass('jumbotron-' ~ variant|lower|replace({'_': '-'})) %}
-{% endif %}
-
 <figure{{ attributes.addClass('figure') }}>
   {{ image|add_class('figure-img') }}
   <figcaption class="figure-caption">

templates/patterns/table/pattern-table.html.twig

@@ -38,7 +38,7 @@
   <div class="{{ 'table-' ~ responsive|lower|replace({'_': '-'}) }}">
 {% endif %}
 
-<table{{ attributes.addClass(table_classes) }}>
+<table{{ attributes }}>
   {% if caption %}
     <caption>{{ caption }}</caption>
   {% endif %}