chore: Tweak APPROVALNOTIFIER markdown template to render consistent …

…HTML

Currently the rendered HTML on gitlab is confusing:

```
This pull-request has been approved by: To complete the pull request process, please assign <user> You can assign the PR to them by writing /lh-assign @<user> in a comment when ready.
```

The above content are in one paragraph without new lines or `.`.

Tweak according to [CommonMark Spec][1], since both [GitHub Flavored Markdown
Spec][2] and [GitLab Flavored Markdown][3] are based on it.

This also add a missing newline before `To complete ...`, so it will take
it's own paragraph.

[1]: https://spec.commonmark.org/0.31.2/#hard-line-breaks
[2]: https://github.github.com/gfm/#hard-line-breaks
[3]: https://gitlab.com/gitlab-org/gitlab/-/blob/master/doc/user/markdown.md#newlines

pkg/plugins/approve/approvers/owners.go

@@ -638,10 +638,10 @@ Approval requirements bypassed by manually added approval.
 {{end -}}
 This pull-request has been approved by:{{range $index, $approval := .ap.ListApprovals}}{{if $index}}, {{else}} {{end}}{{$approval}}{{end}}
 
-{{- if (and (not .ap.AreFilesApproved) (not (call .ap.ManuallyApproved))) }}
-To complete the [pull request process](https://git.k8s.io/community/contributors/guide/owners.md#the-code-review-process), please assign {{range $index, $cc := .ap.GetCCs}}{{if $index}}, {{end}}**{{$cc}}**{{end}}
+{{ if (and (not .ap.AreFilesApproved) (not (call .ap.ManuallyApproved))) -}}
+To complete the [pull request process](https://git.k8s.io/community/contributors/guide/owners.md#the-code-review-process), please assign {{range $index, $cc := .ap.GetCCs}}{{if $index}}, {{end}}**{{$cc}}**{{end}}.  
 You can assign the PR to them by writing `+"`/{{.lhPrefix}}assign {{range $index, $cc := .ap.GetQuotedCCs .providerType}}{{if $index}} {{end}}@{{$cc}}{{end}}`"+` in a comment when ready.
-{{- end}}
+{{ end -}}
 
 {{if not .ap.RequireIssue -}}
 {{else if .ap.AssociatedIssue -}}