fix(examples): correct color parameter in alice.jl wordcloud example

Author: guo-yong-zhi

examples/alice.jl

@@ -2,7 +2,7 @@ using WordCloud
 wc = wordcloud(
     processtext(open(pkgdir(WordCloud) * "/res/alice.txt"), stopwords_extra=["said"]), 
     mask=pkgdir(WordCloud) * "/res/alice_mask.png",
-    color="#faeef8",
+    maskcolor="#faeef8",
     colors=:seaborn_dark,
     angles=(0, 90),
     density=0.55,