incoming: enable pager

The design of incoming means we have to activate the pager in several
places, depending on which codepath gets chosen.

mercurial/commands.py

@@ -3210,6 +3210,7 b' def incoming(ui, repo, source="default",'
             cmdutil.displaygraph(ui, repo, revdag, displayer,
                                  graphmod.asciiedges)
 
+        ui.pager('incoming')
         hg._incoming(display, lambda: 1, ui, repo, source, opts, buffered=True)
         return 0
 
@@ -3223,11 +3224,13 b' def incoming(ui, repo, source="default",'
         if 'bookmarks' not in other.listkeys('namespaces'):
             ui.warn(_("remote doesn't support bookmarks\n"))
             return 0
+        ui.pager('incoming')
         ui.status(_('comparing with %s\n') % util.hidepassword(source))
         return bookmarks.incoming(ui, repo, other)
 
     repo._subtoppath = ui.expandpath(source)
     try:
+        ui.pager('incoming')
         return hg.incoming(ui, repo, source, opts)
     finally:
         del repo._subtoppath