[MINOR][DOC] Fix the link of 'Getting Started'

[mcavdar]

What changes were proposed in this pull request?

Easy fix in the link.

How was this patch tested?

Tested manually

[srowen]

This is fine @mcavdar . While we're at it, there's a link to https://mesos.apache.org/documentation/latest/mesos-frameworks/ that looks dead too -- do you know where that goes?

Also -- just a pet peeve of mine -- I think we can use HTTPS URLs wherever supported. Not worth changing for its own sake, but might be worth it if changing these links for other reasons.

And you're welcome to run a link checker to discover more dead links. I know there are more.

[mcavdar]

It has already been fixed. 01f183e
I'm running a link checker to find and fix more.

[HyukjinKwon]

Maybe it's not quite related but do you mind if I ask to fix the below too?

spark/docs/sql-programming-guide.md

Lines 501 to 504 in ccdf21f

	</div>
	</div>
	### Run SQL on files directly

to (just adding a newline)

 </div> 
 </div> 

 ### Run SQL on files directly 

because it currently could break doc rendering as below:

[mcavdar]

@srowen Here is all broken links, it may be useful. Each line contains broken link and parent page (separated by tab). About 75-100 broken links are related to "http(s)://spark.apache.org/docs/latest".

[SparkQA]

Test build #4012 has finished for PR 19996 at commit 029f676.

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

[srowen]

Merged to master