hgweb: wrap {files} of changesetentry() with mappedgenerator

This can't be easily adapted to mappinggenerator because the associated
templates are switched per item.

mercurial/hgweb/webutil.py

@@ -463,7 +463,7 b' def symrevorshortnode(req, ctx):'
     else:
         return short(ctx.node())
 
-def _listfilesgen(tmpl, ctx, stripecount):
+def _listfilesgen(context, tmpl, ctx, stripecount):
     parity = paritygen(stripecount)
     for blockno, f in enumerate(ctx.files()):
         template = 'filenodelink' if f in ctx else 'filenolink'
@@ -502,7 +502,9 b' def changesetentry(web, ctx):'
         changesettag=showtags,
         changesetbookmark=showbookmarks,
         changesetbranch=showbranch,
-        files=list(_listfilesgen(web.tmpl, ctx, web.stripecount)),
+        files=templateutil.mappedgenerator(_listfilesgen,
+                                           args=(web.tmpl, ctx,
+                                                 web.stripecount)),
         diffsummary=lambda **x: diffsummary(diffstatsgen),
         diffstat=diffstats,
         archives=web.archivelist(ctx.hex()),