configitems: register the 'web.collapse' config

mercurial/configitems.py

@@ -603,6 +603,9 b" coreconfigitem('web', 'cacerts',"
 coreconfigitem('web', 'certificate',
     default=None,
 )
+coreconfigitem('web', 'collapse',
+    default=False,
+)
 coreconfigitem('worker', 'backgroundclose',
     default=dynamicdefault,
 )

mercurial/hgweb/hgwebdir_mod.py

@@ -325,7 +325,7 b' class hgwebdir(object):'
         def rawentries(subdir="", **map):
 
             descend = self.ui.configbool('web', 'descend', True)
-            collapse = self.ui.configbool('web', 'collapse', False)
+            collapse = self.ui.configbool('web', 'collapse')
             seenrepos = set()
             seendirs = set()
             for name, path in self.repos: