[SPARK-8909][Documentation] Change the scala example in sql-programmi…

…ng-guide#Manually Specifying Options to be in sync with java,python, R version

Author: Alok Singh <“singhal@us.ibm.com”>

Closes #7299 from aloknsingh/aloknsingh_SPARK-8909 and squashes the following commits:

d3c20ba [Alok Singh] fix the file to .parquet from .json
d476140 [Alok Singh] [SPARK-8909][Documentation] Change the scala example in sql-programming-guide#Manually Specifying Options to be in sync with java,python, R version

docs/sql-programming-guide.md

@@ -828,7 +828,7 @@ using this syntax.
 
 {% highlight scala %}
 val df = sqlContext.read.format("json").load("examples/src/main/resources/people.json")
-df.select("name", "age").write.format("json").save("namesAndAges.json")
+df.select("name", "age").write.format("parquet").save("namesAndAges.parquet")
 {% endhighlight %}
 
 </div>