Remove display:block hint style as we're switching from span to div

[vanitabarrett]

What

Remove display: block from the hint component styles - this is a breaking change.

Why

In #1855 we switched the hint component from having a wrapping span to having a wrapping div. This was to allow block-level HTML elements to be passed in and render as valid HTML. However, we left the display: block CSS on the wrapping element as otherwise this would be a breaking change that required users to update their HTML.

Further details

Related to #2083, but the outcome of that card shouldn't impact this work unless we decide to switch back to an inline element.

Who needs to know about this

Developers, Tech Writer

Done when

• display: block has been removed from the hint component styles
• "Details of breaking change" section below completed to help with writing release notes

Details of breaking change

• which users are affected: users using the hint component HTML
• the change that’s been made: (in 3.8.0) we switched the hint component to use div instead of span to allow block elements inside hints. We’re removing the styling which made the span behave like a block element
• changes users will have to make: update the hint HTML to use a
  rather than a
• impact of users not making those changes: their hints may not be styled correctly