[MINOR][DOCS] Fix wrong data types in JSON Datasets example.

[dongjoon-hyun]

What changes were proposed in this pull request?

This PR fixes the age data types from integer to long in SQL Programming Guide: JSON Datasets.

How was this patch tested?

Manual.

[SparkQA]

Test build #55493 has finished for PR 12290 at commit c4f6964.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[srowen]

Did you verify this is what is printed if you run the example? then that makes sense.

[dongjoon-hyun]

Sure, I verified on master branch.

[dongjoon-hyun]

Other examples in http://spark.apache.org/docs/latest/sql-programming-guide.html also shows long.

By the way, as you requested, I cleanly synced, built and tested this again a minute ago. I hope it helps your review.

scala> val path = "examples/src/main/resources/people.json"
path: String = examples/src/main/resources/people.json

scala> val people = sqlContext.read.json(path)
people: org.apache.spark.sql.DataFrame = [age: bigint, name: string]

scala> people.printSchema()
root
 |-- age: long (nullable = true)
 |-- name: string (nullable = true)

Thank you, @srowen .

[srowen]

Merged to master

[dongjoon-hyun]

Thank you for merging, @srowen .