Include guidelines for reduced motion

[shaypepper]

Many modern browsers as a matter of accessibility allow users to choose to reduce motion in their internet experience. This would be a useful addition to this checklist. Read more from google here.

[wnstn]

@shaypepper I saw this comment come in and totally forgot to respond. We are starting work to fully update our guidelines to represent all the WCAG 2.1 updates which will include this! Thanks for this issue!