Added clarity in selector paths

[drpayyne]

Description

• Added clarity in the differences between / and // XPath selector syntax

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/verification tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)
• Changes to Framework doesn't have backward incompatible changes for tests or have related Pull Request with fixes to tests

[coveralls]

Coverage decreased (-0.6%) to 52.022% when pulling 96b7249 on drpayyne:patch-1 into 4f482ce on magento:master.

[KevinBKozan]

@drpayyne thank you for your contribution! I'll go ahead and review this.

[KevinBKozan]

@drpayyne I added one commit to this just to add backticks around the in-line HTML, and modified the last sentence just a little bit.

Overall a good addition, thanks again for your contribution 👍