docs(cart): clean up formatting of existing cart documentation #1605

Job	Run time
Build (18.19.x)	5m 54s
Compute Packages to Test	58s
Publish	0s
Test (@daffodil/demo, 18.19.x)	2m 1s
Test (@daffodil/authorizenet, 18.19.x)	1m 52s
Test (@daffodil/cart, 18.19.x)	2m 2s
Test (@daffodil/cart-customer, 18.19.x)	1m 40s
Test (@daffodil/cart-store-credit, 18.19.x)	1m 37s
Test (@daffodil/checkout, 18.19.x)	1m 25s
Test (@daffodil/customer-order, 18.19.x)	1m 43s
Test (@daffodil/customer-payment-authorizenet, 18.19.x)	1m 40s
Test (@daffodil/customer-store-credit, 18.19.x)	1m 45s
Test (@daffodil/order, 18.19.x)	2m 5s
Test (@daffodil/paypal, 18.19.x)	1m 42s
Deploy Daff.io / Next	0s
Deploy Daff.io / Production	0s
	26m 24s

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