configitems: register the 'format.aggressivemergedeltas' config

mercurial/configitems.py

@@ -104,6 +104,9 b" coreconfigitem('devel', 'serverrequirece"
 coreconfigitem('devel', 'strip-obsmarkers',
     default=True,
 )
+coreconfigitem('format', 'aggressivemergedeltas',
+    default=False,
+)
 coreconfigitem('hostsecurity', 'ciphers',
     default=None,
 )

mercurial/localrepo.py

@@ -439,7 +439,7 b' class localrepository(object):'
             self.svfs.options['manifestcachesize'] = manifestcachesize
         # experimental config: format.aggressivemergedeltas
         aggressivemergedeltas = self.ui.configbool('format',
-            'aggressivemergedeltas', False)
+                                                   'aggressivemergedeltas')
         self.svfs.options['aggressivemergedeltas'] = aggressivemergedeltas
         self.svfs.options['lazydeltabase'] = not scmutil.gddeltaconfig(self.ui)
         chainspan = self.ui.configbytes('experimental', 'maxdeltachainspan', -1)