[Bug]: `shopify theme dev` has the wrong content type for `/cart.json` requests

[karreiro]

The shopify theme dev has the wrong content type for /cart.json requests:

Notice that the development server returns the expected one on curl tho:

[ConduciveMammal]

It's worth noting that I tested other Shopify JSON endpoints that also return this issue:

• collections.json
• collections/handle.json
• collections/handle/count.json
• products/handle.json

These are a few but at this point, I imagine they all return this way.