Show correct commit sha when viewing single commit diff (go-gitea#27916)

Show the correct sha when viewing a single commit.


![image](https://github.com/go-gitea/gitea/assets/1135157/5f39a84e-11ed-4700-b40b-eb9da6e91bec)

templates/repo/diff/box.tmpl

@@ -53,7 +53,7 @@
 	{{if not .DiffNotAvailable}}
 		{{if and .IsShowingOnlySingleCommit .PageIsPullFiles}}
 			<div class="ui info message">
-				<div>{{ctx.Locale.Tr "repo.pulls.showing_only_single_commit" (ShortSha .BeforeCommitID)}} - <a href="{{$.Issue.Link}}/files?style={{if $.IsSplitStyle}}split{{else}}unified{{end}}&whitespace={{$.WhitespaceBehavior}}&show-outdated={{$.ShowOutdatedComments}}">{{ctx.Locale.Tr "repo.pulls.show_all_commits"}}</a></div>
+				<div>{{ctx.Locale.Tr "repo.pulls.showing_only_single_commit" (ShortSha .AfterCommitID)}} - <a href="{{$.Issue.Link}}/files?style={{if $.IsSplitStyle}}split{{else}}unified{{end}}&whitespace={{$.WhitespaceBehavior}}&show-outdated={{$.ShowOutdatedComments}}">{{ctx.Locale.Tr "repo.pulls.show_all_commits"}}</a></div>
 			</div>
 		{{else if and (not .IsShowingAllCommits) .PageIsPullFiles}}
 			<div class="ui info message">