Improve icon shape and weight

[pseys]

The Pepper and PUI teams have undertaken a review of Salt icons and provided feedback regarding the size, weight, and shape of certain icons.

Help icon

Observation that help icon looks like a missing image/content icon rather than help. Suggested that the icon is changed to a circle containing a question mark as opposed to a square.

Close icon

Observation that close is a heavier weight line than other components and there may be other similar icons that need adjusting

Chevron icons
Based on work by CB and PUI reduce the size of chevron icons within their bounding box

• Carry-out audit of icons to identify other potential problem areas regarding weight, line thickness, or size
• Agree changes required and make amendments where necessary