default mime type text/html for SPA

[JamesKyburz]

When refreshing a page in a SPA the page source is returned as text/plain.

This PR changes the content type to text/html if the single flag is set.

[leo]

Why? What about the JS and CSS assets and vectors, etc.? Aren't they better suited with text/plain than with text/html?

[JamesKyburz]

The assets are returned with the correct mime types. This is because the mime module uses their extensions.

The problem is when the url has no extension, so for example a url in a SPA with /awesome/cats would return text/plain and the html source. In a SPA the default page is index.html.

The problem only occurs if the page is refreshed.

[leo]

👌

[JamesKyburz]

Thanks!