Reformat Markdown files following Google Markdown style guide.
Reformat Markdown files following Google Markdown style guide.

See http://google.github.io/styleguide/docguide/style.html.

Formatting was automated via Google-internal go/mdformat in Github compatibility mode.

Change-Id: Id85bcab4e0e61884b5e406e9df933caaadf9eb9a

world-federation-of-advertisers/cross-media-measurement,world-federation-of-advertisers/cross-media-measurement,world-federation-of-advertisers/cross-media-measurement