[SPARK-4421] Wrong link in spark-standalone.html

Modified the link of building Spark. (backport version of #3279.)

Author: Masayoshi TSUZUKI <tsudukim@oss.nttdata.co.jp>

Closes #3280 from tsudukim/feature/SPARK-4421-2 and squashes the following commits:

3b4d38d [Masayoshi TSUZUKI] [SPARK-4421] Wrong link in spark-standalone.html
Fix typo in Spark SQL docs.

Author: Andy Konwinski <andykonwinski@gmail.com>

Closes #3611 from andyk/patch-3 and squashes the following commits:

7bab333 [Andy Konwinski] Fix typo in Spark SQL docs.

(cherry picked from commit 15cf3b0125fe238dea2ce13e703034ba7cef477f)
Signed-off-by: Josh Rosen <joshrosen@databricks.com>