Bug 1391596 - Add cockatiel to the en-US dictionary. r=ehsan

extensions/spellcheck/locales/en-US/hunspell/en-US.dic

@@ -1,4 +1,4 @@
-52361
+52362
 0/nm
 0th/pt
 1/n1
@@ -19770,6 +19770,7 @@ cochlear
 cock/MDGS
 cockade/SM
 cockamamie
+cockatiel/SM
 cockatoo/SM
 cockatrice/SM
 cockchafer/S