Add documentation of all CSS variables available

docs/documentation/form/file.html

@@ -450,7 +450,3 @@ meta:
 </div>
 
 {% include docs/elements/snippet.html horizontal=true content=file_javascript %}
-{%
-  include docs/components/variables.html type='element'
-  variables_keys=page.variables_keys folder='elements' file='form'
-%}

docs/documentation/form/general.html

@@ -1108,14 +1108,3 @@ variables_keys:
   folder='utilities'
   file='controls'
 %}
-
-{%
-  include docs/components/variables.html
-  anchor_name='Form variables'
-  type='element'
-  variables_keys=page.variables_keys
-  folder='elements'
-  file='form'
-  hide_anchor=true
-  hide_content=true
-%}

docs/documentation/form/input.html

@@ -442,8 +442,3 @@ meta:
     {%- endhighlight %}
   </div>
 </div>
-
-{%
-  include docs/components/variables.html type='element'
-  variables_keys=page.variables_keys folder='elements' file='form'
-%}

docs/documentation/form/textarea.html

@@ -12,7 +12,7 @@ breadcrumb:
 meta:
   colors: true
   sizes: true
-  variables: false
+  variables: true
 ---
 {% capture textarea_example %}
 <textarea class="textarea" placeholder="e.g. Hello world"></textarea>