Unexpected newline in commit messages with signed-off metadata
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### Summary
When using (at least) a `Signed-off-by` marking in a commit message, GitLab's commit view will present a commit message with leading empty newlines.
### Steps to reproduce
Create a commit with the following example content and push into a branch:
```
my subject
This is my content.
Signed-off-by: My Example <my@example.com>
```
Then view the commit on GitLab and observe that an extract newline is render.
### Example Project
The commit https://gitlab.com/jdknight/git-commit-formatting/-/commit/aa7092ffb17d612067614a3ba71b69bc5ee05707 without a sign-off marking with a nicely formatted message, where the commit https://gitlab.com/jdknight/git-commit-formatting/-/commit/671b0c5fb0d198441ccfd48bbcb45f1fc2950419 with a sign-off marking includes an undesired newline at the start.
### What is the current *bug* behavior?
Empty leading newlines exists in the rendered commit message.
### What is the expected *correct* behavior?
Empty leading newlines should be removed in the rendered commit message.
### Relevant logs and/or screenshots
The follow rendering shows an unexpected newline spacing:
{width=620 height=453}
### Output of checks
This bug happens on GitLab.com.
#### Results of GitLab environment info
n/a
#### Results of GitLab application Check
n/a
### Possible fixes
It appears in this scenario that the content is not removing empty lines the start:
{width=445 height=147}
The rendering logic should be stripping empty newlines at the start of a message (after the title extraction; important to not left strip the entire message if there is indented content to render).
issue