help: test keyword search in translated text.

Tests that help keyword search is able to search the translated help text when
using a non-English language.

tests/test-i18n.t

@@ -1,24 +1,36 b''
 Translations are optional:
 
   $ "$TESTDIR/hghave" gettext || exit 80
 
 Test that translations are compiled and installed correctly.
 
 Default encoding in tests is "ascii" and the translation is encoded
 using the "replace" error handler:
 
   $ LANGUAGE=pt_BR hg tip
   abortado: n?o foi encontrado um reposit?rio em '$TESTTMP' (.hg n?o encontrado)!
   [255]
 
 Using a more accomodating encoding:
 
   $ HGENCODING=UTF-8 LANGUAGE=pt_BR hg tip
   abortado: n\xc3\xa3o foi encontrado um reposit\xc3\xb3rio em '$TESTTMP' (.hg n\xc3\xa3o encontrado)! (esc)
   [255]
 
 Different encoding:
 
   $ HGENCODING=Latin-1 LANGUAGE=pt_BR hg tip
   abortado: n\xe3o foi encontrado um reposit\xf3rio em '$TESTTMP' (.hg n\xe3o encontrado)! (esc)
   [255]
+
+Test keyword search in translated help text:
+
+  $ HGENCODING=UTF-8 LANGUAGE=de hg help -k blättern
+  Topics:
+  
+   extensions Using Additional Features
+  
+  Erweiterungen:
+  
+   pager Verwendet einen externen Pager zum Bl\xc3\xa4ttern in der Ausgabe von Befehlen (esc)
+