Simplify Google Fonts link element

[thibaudcolas]

Simplifies the link element used for Google Fonts, so it’s easier for beginners to follow:

• Its attributes should use the same quote style as other elements.
• rel="stylesheet" should come first, to match other link elements.
• No need for a protocol-relative URL, we can load the HTTPS version everywhere.
• type="text/css" does nothing, it can be removed.

[das-g]

Thank you!