Fix html escaping non strings

[camertron]

See: #1958

[reeganviljoen]

@camertron this is also happening with other types such as json can you add a test for that

[camertron]

@reeganviljoen I'm not sure a test for JSON is necessary, since html_escape({}) returns "{}" and calling #to_json on a hash or array returns a string. In all cases, escaping it should be fine if it's being emitted in an HTML context.

[camertron]

PVC failures are unrelated to this change, i.e. are non-blocking 👍