CSS `exp()` function - Add two examples, add return value and update description

[ramiy]

Description

@wbamberg requested to add a couple of examples - https://github.com/mdn/content/pull/20826#pullrequestreview-1112765075

Motivation

Should have been part of #20826 but I haven't finished testing the examples...

Related issues and pull requests

Relates to #20826

[github-actions[bot]]

Preview URLs

• /en-US/docs/Web/CSS/exp

External URLs (1)

URL: /en-US/docs/Web/CSS/exp Title: exp()

• https://en.wikipedia.org/wiki/E_(mathematical_constant) (1 time) (Note! This may be a new URL 👀)

(this comment was updated 2022-11-23 05:54:07.832043)