manifestcache: test and fix some output of the debug command

manifestcache: test and fix some output of the debug command

The message was lacking an end of line. In addition we do not capitalize output
in Mercurial.

--- a/mercurial/debugcommands.py	Thu Dec 27 13:36:17 2018 -0800
+++ b/mercurial/debugcommands.py	Thu Mar 14 09:11:18 2019 +0000
@@ -1486,7 +1486,7 @@
             manifest.read()  # stores revisision in cache too
 
         if not len(cache):
-            ui.write(_('Cache empty'))
+            ui.write(_('cache empty\n'))
         else:
             ui.write(
                 _('Cache contains %d manifest entries, in order of most to '

--- a/tests/test-manifest.t	Thu Dec 27 13:36:17 2018 -0800
+++ b/tests/test-manifest.t	Thu Mar 14 09:11:18 2019 +0000
@@ -93,3 +93,17 @@
   $ hg manifest -r tip tip
   abort: please specify just one revision
   [255]
+
+Testing the manifest full text cache utility
+--------------------------------------------
+
+Reminder of the manifest log content
+
+  $ hg log --debug | grep 'manifest:'
+  manifest:    1:1e01206b1d2f72bd55f2a33fa8ccad74144825b7
+  manifest:    0:fce2a30dedad1eef4da95ca1dc0004157aa527cf
+
+Showing the content of the caches after the above operations
+
+  $ hg debugmanifestfulltextcache
+  cache empty