locale/README.md: Copyediting

[reedy]

Description

Various editing of locale README.me

Rationale

Phabricator Ticket

n/a

How Has This Been Tested?

n/a

Screenshots of your changes (if appropriate):

n/a

Types of changes

What types of changes does your code introduce? Add an x in all the boxes that apply:

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Minor change (fix a typo, add a translation tag, add section to README, etc.)