[New Tip] Design tip no6 - easily identifiable feedback

[dboudreau]

Reference: http://w3c.github.io/wai-quick-start/designing.html#provide-easily-identifiable-feedback

The tip currently reads:

Provide easily identifiable feedback Provide feedback for interactions, such as confirming form submission, alerting the user when something goes wrong, or notifying the user of changes on the page. Instructions should be easy to identify. Important feedback that requires user action should be presented in a prominent style.

Proposing we change to:

Provide easily identifiable feedback Provide feedback for interactions, such as confirming form submission, alerting the user when something goes wrong, or notifying the user of changes on the page. Instructions should be easy to identify and suggestions to help fix issues whenever errors are returned must be provided. Important feedback that requires user action should be presented in a prominent style.