fenced_code: Add `process_contents` flag to de-duplicate code.
fenced_code: Add `process_contents` flag to de-duplicate code.

hackerkid/zulip,rht/zulip,hackerkid/zulip,andersk/zulip,rht/zulip,andersk/zulip,kou/zulip,eeshangarg/zulip,rht/zulip,kou/zulip,kou/zulip,zulip/zulip,hackerkid/zulip,hackerkid/zulip,kou/zulip,zulip/zulip,zulip/zulip,hackerkid/zulip,kou/zulip,rht/zulip,andersk/zulip,andersk/zulip,eeshangarg/zulip,kou/zulip,andersk/zulip,andersk/zulip,rht/zulip,eeshangarg/zulip,hackerkid/zulip,zulip/zulip,eeshangarg/zulip,rht/zulip,zulip/zulip,eeshangarg/zulip,eeshangarg/zulip,kou/zulip,rht/zulip,andersk/zulip,zulip/zulip,hackerkid/zulip,eeshangarg/zulip,zulip/zulip