Add automatic links to Sentry issues
### Problem to solve
After Sentry integration became available (https://about.gitlab.com/2019/02/22/gitlab-11-8-released/#error-tracking-with-sentry) users are able to see current errors list in Gitlab. However there could be also issues ID in commit messages ("Fixes SENTRYBUG-6F") and it would be nice to have automatic links highlight after integration was set up.
### Intended users
Unknown
### Further details
<!-- Include use cases, benefits, and/or goals (contributes to our vision?) -->
### Proposal
Make text links in commit text clickable as a link going to original Sentry issue.
### Permissions and Security
N/A
<!-- What permissions are required to perform the described actions? Are they consistent with the existing permissions as documented for users, groups, and projects as appropriate? Is the proposed behavior consistent between the UI, API, and other access methods (e.g. email replies)? -->
### Documentation
N/A
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### Testing
Can be potential conflicts with "Custom issue tracker", needs testing in this area.
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### What does success look like, and how can we measure that?
Sentry issues IDs are clickable in commit messages.
<!-- Define both the success metrics and acceptance criteria. Note that success metrics indicate the desired business outcomes, while acceptance criteria indicate when the solution is working correctly. If there is no way to measure success, link to an issue that will implement a way to measure this. -->
### Links / references
issue