fix(collections): 🐛 diamond, ajustes no texto

Author: rcmoutinho

book/08-java-collections/sections/01-diamond.asc

@@ -18,6 +18,7 @@ O Diamond Operator (ou Operador Diamante) foi criado no Java 7 para remover cód
 include::{section-java-package}/diamond/Collections_Diamond.java[tag=code]
 ----
 
+.Referências
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 * Using the Diamond Operator
@@ -26,4 +27,4 @@ Boyarsky, Jeanne; Selikoff, Scott. OCP: Oracle Certified Professional Java SE 8
 
 * https://www.baeldung.com/java-diamond-operator[Guide to the Diamond Operator in Java.]
 
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