keyword: do not bother about detecting extension path in demo

Detecting and showing the path to a keyword extension in a
non-standard place only made sense while keyword.py was not
shipped with Mercurial.

The test output has changed because we do not have a spurious
space at eol anymore.

hgext/keyword.py

@@ -322,11 +322,7 b' def demo(ui, repo, *args, **opts):'
 
     uisetup(ui)
     reposetup(ui, repo)
-    for k, v in ui.configitems('extensions'):
-        if k.endswith('keyword'):
-            extension = '%s = %s' % (k, v)
-            break
-    ui.write('[extensions]\n%s\n' % extension)
+    ui.write('[extensions]\nkeyword =\n')
     demoitems('keyword', ui.configitems('keyword'))
     demoitems('keywordmaps', kwmaps.iteritems())
     keywords = '$' + '$\n$'.join(sorted(kwmaps.keys())) + '$\n'