title: geom_emoji() function does not accept input if it's stored in a variable
body: <p>I am trying to include emojis in a plot created with R and ggplot2. I´m currently using the emoGG package, specifically the <code>geom_emoji()</code> function. The weird thing is that I can pass the emoji name as a character string but I cannot assign the character string to a variable and use that instead. This makes it impossible to automate the assignment with a lookup table. Here is an example of what I mean:</p>
  
  <pre><code># Reproducible Example
  
  # packages
  library(emoGG)
  library(ggplot2)
  
  # Example (works)
  ggplot(iris, aes(Sepal.Length, Sepal.Width, color = Species)) +
    geom_emoji(emoji="1f337")
  
  
  # Doesn't work (Error: Not Found)
  Pic &lt;- "1f337"
  ggplot(iris, aes(Sepal.Length, Sepal.Width, color = Species)) +
    geom_emoji(emoji=Pic)
  
  # Identical
  identical("1f337",Pic)
  </code></pre>