Jira Desktop on macOS shouldn't send message when we hit enter by default

On macOS there is a Jira client available on the AppStore.

This look like a great product to use with native notification support and everything, however, there is a UX issue regarding the comment form.

Indeed, unlike the web version, when we hit enter in the comment form, it send the message by default instead of doing a line break.

Current behavior isn't explicit:

• there is no user settings for that
• there is no label explaining what action do what (enter to send, alt enter for a line break)
• there is a send button visible, which isn't the common UX for forms that validate with enter

You should add a label to avoid confusion, and let this behavior to the end user choice.

When we use the Jira Desktop client to use with Jira Service Desk, message will be sent to company's customers, we need to be able to do proper text formating in that situation.