core/fetch: Also do image proxying on the "content" field.
core/fetch: Also do image proxying on the "content" field.

Some feeds set this field instead of "summary" and we prefer it over
"summary" when choosing what to display.

jrupac/goliath,jrupac/goliath,jrupac/goliath,jrupac/goliath,jrupac/goliath