[MINOR][DOCS] Fix all typos in markdown files of `doc` and similar patterns in other comments

## What changes were proposed in this pull request?

This PR tries to fix all typos in all markdown files under `docs` module,
and fixes similar typos in other comments, too.

## How was the this patch tested?

manual tests.

Author: Dongjoon Hyun <dongjoon@apache.org>

Closes #11300 from dongjoon-hyun/minor_fix_typos.

1 files changed, 1 insertions, 1 deletions

diff --git a/docs/programming-guide.md b/docs/programming-guide.md
index 2d6f7767d9..5ebafa40b0 100644
--- a/docs/programming-guide.md
+++ b/docs/programming-guide.md
@@ -629,7 +629,7 @@ class MyClass {
 }
 {% endhighlight %}
 
-is equilvalent to writing `rdd.map(x => this.field + x)`, which references all of `this`. To avoid this
+is equivalent to writing `rdd.map(x => this.field + x)`, which references all of `this`. To avoid this
 issue, the simplest way is to copy `field` into a local variable instead of accessing it externally:
 
 {% highlight scala %}