Class: TwentyNineteen_SVG_Icons  - X-Ref

This class is in charge of displaying SVG icons across the site.

Place each <svg> source on its own array key, without adding the
both `width` and `height` attributes, since these are added dynamically,
before rendering the SVG code.

All icons are assumed to have equal width and height, hence the option
to only specify a `$size` parameter in the svg methods.