Uptil now, 1 new line was added before and 1 after a quoted message. Now
for more breathing room around a quoted message, new lines are inserted
to space it from any content before and after by at least 2 new lines.
Fixes: #23608.
This lets us simplify the long-ish ‘../../static/js’ paths, and will
remove the need for the ‘zrequire’ wrapper.
Signed-off-by: Anders Kaseorg <anders@zulip.com>