Use "Safe" modifier for manually constructed safe HTML strings in templates (#29227)

Follow #29165. These HTML strings are safe to be rendered directly, to
avoid double-escaping.

templates/repo/settings/webhook/settings.tmpl

@@ -263,7 +263,7 @@
 	<label for="authorization_header">{{ctx.Locale.Tr "repo.settings.authorization_header"}}</label>
 	<input id="authorization_header" name="authorization_header" type="text" value="{{.Webhook.HeaderAuthorization}}"{{if eq .HookType "matrix"}} placeholder="Bearer $access_token" required{{end}}>
 	{{if ne .HookType "matrix"}}{{/* Matrix doesn't make the authorization optional but it is implied by the help string, should be changed.*/}}
-		<span class="help">{{ctx.Locale.Tr "repo.settings.authorization_header_desc" "<code>Bearer token123456</code>, <code>Basic YWxhZGRpbjpvcGVuc2VzYW1l</code>" | Str2html}}</span>
+		<span class="help">{{ctx.Locale.Tr "repo.settings.authorization_header_desc" ("<code>Bearer token123456</code>, <code>Basic YWxhZGRpbjpvcGVuc2VzYW1l</code>" | Safe)}}</span>
 	{{end}}
 </div>