Wrap brevity statement in a comment block for consistency.
Switch from html syntax to handlebars syntax.
Replace html comment syntax with handlebars syntax.

This switches out the html comment syntax `<!-- -->` with the handlebars syntax flavor `{{! }}`
in the getting started guide.
Merge pull request #1707 from johnotander/wrap-brevity-statement-in-comment-block

Wrap brevity statement in a comment block for consistency.