Use consistent and semantically correct HTML elements in the Cart and Checkout blocks

[nielslange]

Note

Currently, similar looking elements in the Cart and the Checkout block, are using different HTML markup. This issue aims to use consistent and semantically correct HTML elements. This issue is part of #8710 and the result of pdFofs-SY-p2.

Steps to reproduce

1. Add a test product to the cart.
2. Go to the cart page.
3. See that the titles PRODUCT and TOTAL use a <span> element, while the title CART TOTALS uses an <h2> element.
4. Go to the checkout page.
5. See that the title Order summary uses an <h2> element, while the titles Subtotal, Shipping, Tax and Total use a <span> element.

Expected outcome

• The title CART TOTALS uses a <span> element instead of an <h2> element.
• The title Order summary uses a <span> element instead of an <h2> element.

[nielslange]

Closing this, as the issue had been fixed with #9065.