hgweb: wrap {archives} with mappinglist

No bare list of mappings should be put in a template mapping.

mercurial/hgweb/hgwebdir_mod.py

@@ -172,7 +172,7 b' def rawindexentries(ui, repos, req, subd'
                    'description_sort': "",
                    'lastchange': d,
                    'lastchange_sort': d[1] - d[0],
-                   'archives': [],
+                   'archives': templateutil.mappinglist([]),
                    'isdirectory': True,
                    'labels': templateutil.hybridlist([], name='label'),
                    }

mercurial/hgweb/webutil.py

@@ -35,6 +35,7 b' from .. import ('
     scmutil,
     templatefilters,
     templatekw,
+    templateutil,
     ui as uimod,
     util,
 )
@@ -63,7 +64,7 b' def archivelist(ui, nodeid, url=None):'
                 'url': url,
             })
 
-    return archives
+    return templateutil.mappinglist(archives)
 
 def up(p):
     if p[0:1] != "/":