Add alt text

[sierraobryan]

Use semanticLabel: 'Alt text'

Examples of what should have alt text:

• image: what is the image of? (example: Image of member's name)
• buttons: what does the button do? (example: navigate to name of link)
• icons: what is the icon of? (example: twitter icon)

Some examples of what does not need alt text:

• text widgets
• parent container