Make css-grid example more semantic

[vansosnin]

What this PR does

Wraps images into buttons to better interactivity using the keyboard.

Requirements

• My PR follows all applicable accessibility requirements (See .github/ACCESSIBILITY_REQS.md).
• My PR follows the CSS code style guidelines (See .github/CSS_STYLE_REQS.md).
• I have linted my code using npm run lint:css -- demoDirectoryName/**/*.css and npm run lint:js -- demoDirectoryName/**/*.js, and have fixed the errors.

[msftclas]

All CLA requirements met.

[ststimac]

I'm pretty sure @gregwhitworth is the one who wrote the code for this.

[ghost]

Looks good..!

[gregwhitworth]

Sorry for the delay on this and thank you for taking the time @vansosnin

You have changed the name computation by putting the img within the <button> which removes the audio only game that was built into the game (see "How to play" section). If you can please modify your code so that when you traverse to the button the word is read out loud allowing audio only users to build out the phrase and have a similiar puzzle experience but in a different dimension.

Please at-mention me upon completion so I get an email about the change. Thank you!

[vansosnin]

@gregwhitworth thanks, and it's done