Alternative UX for action buttons related to batch review comments
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# Summary
Current button layout/wording of review comment field does not clarify upfront that which button adds comment instantly and which button starts a review where posting of comment is held off until final comment for bulk posting. Learn more about this in [Slack discussion](https://gitlab.slack.com/archives/C0GQHHPGW/p1540215175000100).

# Proposal
This issue is open to alternative ideas in which we can fix this by either rewording buttons, tweaking button colors or layout.
# Competition Examples
### GitHub

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