HTTP header WWW-Authenticate realm should be double-quoted

[tstrg]

HTTP header WWW-Authenticate realm should be double-quoted to be valid.

The example Realm: "test zone" should be changed to Realm: "\"test zone\"",

For reference see https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/WWW-Authenticate (includes links to RFCs)

https://tools.ietf.org/html/rfc7235#section-5.1.2 mentions the fact that the value syntax for the "realm" parameter is restricted to quoted-string.