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'

tests/test-keyword.out

@@ -1,6 +1,6 b''
 % hg kwdemo
 [extensions]
-keyword = 
+keyword =
 [keyword]
 demo.txt = 
 [keywordmaps]
@@ -21,7 +21,7 b' Source = {root}/{file},v'
 $Revision: xxxxxxxxxxxx $
 $Source: /TMP/demo.txt,v $
 [extensions]
-keyword = 
+keyword =
 [keyword]
 demo.txt = 
 [keywordmaps]
@@ -206,7 +206,7 b' 0 files updated, 0 files merged, 0 files'
 % custom keyword expansion
 % try with kwdemo
 [extensions]
-keyword = 
+keyword =
 [keyword]
 * = 
 b = ignore