Review theme/widget markup

[lukefretwell]

I've noticed some issues related to widgets where the markup isn't ideal and would love to do cleanup sprint on this. Using this issue to document these:

• Report from W3C Nu Html Checker: https://validator.w3.org/nu/?doc=https%3A%2F%2Fexample.proudcity.com%2Fwidgets%2F
• See screenshots below

Review resources to help validate:

• https://validator.w3.org/ (use as base: https://example.proudcity.com/)
• http://jigsaw.w3.org/css-validator/
• https://achecker.ca/checker/index.php
• https://w3c.github.io/developers/tools/

[lukefretwell]

Example:

[lukefretwell]

PAC is showing a markup warning here:

[lukefretwell]