Fix code block indentation (#146)

Author: Chris Cho

source/java/sql.txt

@@ -4,9 +4,9 @@
 
 .. code-block:: java
 
-		implicitDS.createOrReplaceTempView("characters");
-		Dataset<Row> centenarians = spark.sql("SELECT name, age FROM characters WHERE age >= 100");
-		centenarians.show();
+   implicitDS.createOrReplaceTempView("characters");
+   Dataset<Row> centenarians = spark.sql("SELECT name, age FROM characters WHERE age >= 100");
+   centenarians.show();
 
 ``centenarians.show()`` outputs the following: