Merge pull request #3744 from department-of-veterans-affairs/download-link-guidance

Update link/button guidance for downloads

Author: rsmithadhoc

src/_includes/content/links-vs-buttons.md

@@ -4,3 +4,4 @@
 - It is important to use Action Links for calls to actions that link to another page rather than buttons, because screen readers always say “link” before links, and “button” before buttons. 
 - A good rule is if the action changes the URL, it should not be a button.
 - Button and link confusion can be very frustrating for assistive technology users. A user with a screen reader may pull up a list of links and may not find a specific link because it turns out that it’s been designated as a button in the markup.
+- When a file download is involved, it is best to use a link. This is because links are intended for navigation, and downloading a file is a navigational action to a resource.