[DOCS] Fix typo in documentation for Java UDF registration

This contribution is my original work and I license the work to the project under the project's open source license

Author: Matt Wise <[email protected]>

Closes apache#6447 from wisematthew/fix-typo-in-java-udf-registration-doc and squashes the following commits:

e7ef5f7 [Matt Wise] Fix typo in documentation for Java UDF registration

Author: wisematthew

docs/sql-programming-guide.md

@@ -1939,7 +1939,7 @@ sqlContext.udf.register("strLen", (s: String) => s.length())
 <div data-lang="java"  markdown="1">
 {% highlight java %}
 
-sqlContext.udf().register("strLen", (String s) -> { s.length(); });
+sqlContext.udf().register("strLen", (String s) -> s.length(), DataTypes.IntegerType);
 
 {% endhighlight %}
 </div>