title: Liquid nesting variable output into a variable name
body: <p>I have the following challenge within my Shopify Shop.</p>
  <p>I'm using ACF (Advanced Custom Fields) if I want to use it I use this code in my frontend:
  <code>{{product.metafields.warnhinweise.not-under-three-years}}</code> the Output is: <code>true</code></p>
  <p>Now I want to output a variable from the translation file (locals/de.json), to access this variable I have to use: <code>{{ 'products.productwarnings.not-under-three-years' | t }}</code></p>
  <p>What I want to accomplish and where I currently struggle is: How could I pass the ID from my custom field as a variable name from my translation-variable?</p>
  <p>I tried the following:</p>
  <pre><code>&lt;p&gt;Example: {{ product.metafields.warnhinweise.not-under-three-years }}&lt;/p&gt;
  &lt;ul&gt;
    {% for field in product.metafields.warnhinweise %}
    &lt;li&gt;ID: {{ field | first }} - Value: {{ field | last }}&lt;/li&gt;
      &lt;ul&gt;
        &lt;li&gt;normal way: {{ 'products.productwarnings.not-under-three-years' | t }}&lt;/li&gt;
        &lt;li&gt;nest the variable output: {{ 'products.productwarnings.{{field | first}}'  | t }}&lt;/li&gt;
      &lt;/ul&gt;
    {% endfor %}
  &lt;/ul&gt;
  </code></pre>
  <p>But obviously, this will not work. How could I accomplish to insert {{field | first}} into my translation-variable?</p>
  <p>The output of the above code is the following:</p>
  <pre><code>Example: true
  
   - ID: not-under-three-years - Value: true
     - normal way: Achtung: Nicht für Kinder unter drei Jahren geeignet.
     - nest the variable output: translation missing: de.products.productwarnings.field | first
  </code></pre>
  <p>Also I get an syntax error from liquid: <code>[dev-henry] (sections/product-template.liquid) Liquid syntax error (line 220): Unexpected character ' in &quot;{{ 'products.productwarnings.field | first  | t }}&quot;</code></p>