This commit modifies the regex used when parsing JIRA's full links of
the form `[text|link]` so that if you have two in a message, Zulip
markup conversion doesn't think that the first link extends to the
closing `]` of the second link.
comment_created payloads may not contain the required issue data
to format a useful notification, therefore, it is better to handle
issue comments through issue_updated events (which we already do).
Fixes: #11995.
All webhook fixtures in zerver/fixtures/<webhook_name> have now
been moved to dedicated webhook-specific directories under
zerver/webhooks/<webhook_name>/fixtures, where <webhook_name> is
the name of the webhook.
David Wood
Eeshan Garg