Do not emit ambiguous character warning on rendered pages (#22016) (#22018)

Backport #22016

The real sensitivity of ambiguous characters is in source code -
therefore warning about them in rendered pages causes too many warnings.
Therefore simply remove the warning on rendered pages.

The escape button will remain available and it is present on the view
source page.

Fix #20999

Signed-off-by: Andrew Thornton <art27@cantab.net>

templates/repo/view_file.tmpl

@@ -79,7 +79,9 @@
 		</div>
 	</h4>
 	<div class="ui attached table unstackable segment">
+		{{if not (or .IsMarkup .IsRenderedHTML)}}
 			{{template "repo/unicode_escape_prompt" dict "EscapeStatus" .EscapeStatus "root" $}}
+		{{end}}
 		<div class="file-view{{if .IsMarkup}} markup {{.MarkupType}}{{else if .IsRenderedHTML}} plain-text{{else if .IsTextSource}} code-view{{end}}">
 			{{if .IsMarkup}}
 				{{if .FileContent}}{{.FileContent | Safe}}{{end}}