Tweak pull request branch delete ui (#23951)

- Move delete button to right and remove red color on it.
- Remove CLI instructions when PR has been merged.

Before:

<img width="855" alt="Screenshot 2023-04-06 at 20 21 47"
src="https://user-images.githubusercontent.com/115237/230463178-95735fc0-9632-4d51-bbd5-2131c40186c4.png">

After:

<img width="865" alt="Screenshot 2023-04-06 at 20 23 17"
src="https://user-images.githubusercontent.com/115237/230463347-8155cbf9-4e58-421a-93a8-56ce6188dab8.png">

After (deleted):

<img width="860" alt="Screenshot 2023-04-06 at 20 19 30"
src="https://user-images.githubusercontent.com/115237/230463442-f53d7500-191d-4d75-a097-d100a461672a.png">

---------

Co-authored-by: Giteabot <teabot@gitea.io>

options/locale/locale_en-US.ini

@@ -1623,11 +1623,11 @@ pulls.tab_files = Files Changed
 pulls.reopen_to_merge = Please reopen this pull request to perform a merge.
 pulls.cant_reopen_deleted_branch = This pull request cannot be reopened because the branch was deleted.
 pulls.merged = Merged
-pulls.merged_as = The pull request has been merged as <a rel="nofollow" class="ui sha" href="%[1]s"><code>%[2]s</code></a>.
+pulls.merged_success = Pull request successfully merged and closed
+pulls.closed = Pull request closed
 pulls.manually_merged = Manually merged
-pulls.manually_merged_as = The pull request has been manually merged as <a rel="nofollow" class="ui sha" href="%[1]s"><code>%[2]s</code></a>.
+pulls.merged_info_text = The branch %s can now be deleted.
 pulls.is_closed = The pull request has been closed.
-pulls.has_merged = The pull request has been merged.
 pulls.title_wip_desc = `<a href="#">Start the title with <strong>%s</strong></a> to prevent the pull request from being merged accidentally.`
 pulls.cannot_merge_work_in_progress = This pull request is marked as a work in progress.
 pulls.still_in_progress = Still in progress?