[Site] Fix UX Translator demo on "price" parameter

Spotted while working on symfony#3080

Author: Kocal

ux.symfony.com/templates/ux_packages/translator.html.twig

@@ -158,14 +158,14 @@
         {% embed 'ux_packages/translator/_translator_demo_block.html.twig' with {
             message: 'VALUE_OF_OBJECT',
             parameters: {
-                value: 30
+                price: 30
             },
         } %}
             {% block parameters %}
                 <div>
-                    <label for="VALUE_OF_OBJECT-value" class="small opacity-50">Value</label>
-                    <input id="VALUE_OF_OBJECT-value" class="form-control"
-                           name="value" type="number" min="1"  value="30" step="0.1"
+                    <label for="VALUE_OF_OBJECT-price" class="small opacity-50">Price</label>
+                    <input id="VALUE_OF_OBJECT-price" class="form-control"
+                           name="price" type="number" min="1"  value="30" step="0.1"
                            data-translator-demo-block-target="parameters"
                            data-action="translator-demo-block#render"
                     >

ux.symfony.com/translations/messages+intl-icu.en.yaml

@@ -32,4 +32,4 @@ published_at: 'Published at {publication_date, date} - {publication_date, time,
 
 # Numbers
 progress: '{progress, number, percent} of the work is done'
-value_of_object: 'This artifact is worth {value, number, ::currency/EUR}'
+value_of_object: 'This artifact is worth {price, number, ::currency/EUR}'

ux.symfony.com/translations/messages+intl-icu.fr.yaml

@@ -30,4 +30,4 @@ published_at: 'Publié le {publication_date, date} - {publication_date, time, sh
 
 # Numbers
 progress: '{progress, number, percent} du travail est fait'
-value_of_object: "Cet artéfact vaut {value, number, ::currency/EUR}"
+value_of_object: "Cet artéfact vaut {price, number, ::currency/EUR}"