Fix wordcloud plotting error in cloud_pie()

[matt-dray]

Post: https://www.rostrum.blog/2018/05/25/cloud-pie/

Problem: there's a plotting error with the relative size of more common words.

Warning messages:
1: In wordcloud(words = data[[name_col]], freq = data[[count_col]],  :
  charizard could not be fit on page. It will not be plotted.
2: In wordcloud(words = data[[name_col]], freq = data[[count_col]],  :
  snorlax could not be fit on page. It will not be plotted.

Solution: try with a smaller scale, as in https://stackoverflow.com/questions/27981651/text-wordcloud-plotting-error