title: Concatenation of YAML "anchors" with another string in keys
body: <p>So I want to turn this:</p>
  
  <pre><code>a:
    b: &amp;b "hello"
    c: *b "world"
  </code></pre>
  
  <p>Into this: <code>{"a"=&gt;{"b"=&gt;"hello", "c"=&gt;"hello world"}}</code></p>
  
  <p>But right now I get <code>did not find expected key while parsing a block mapping at line 2 column 3</code>.</p>
  
  <p>I know that this works fine:</p>
  
  <pre><code>a:
    b: &amp;b "hello"
    c: *b
  </code></pre>
  
  <p>(I learned from <a href="https://learnxinyminutes.com/docs/yaml/" rel="noreferrer">learnxinyminutes</a> and also tries some <code>%() %{} #{} ..</code> syntaxes but none of them worked)</p>