translation: improve the po/cleanup.vim script

explicitly delete into the black-hole register

closes: #15499

Signed-off-by: RestorerZ <restorer@mail2k.ru>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/po/cleanup.vim b/src/po/cleanup.vim
index 1af188a..5e1b967 100644
--- a/src/po/cleanup.vim
+++ b/src/po/cleanup.vim
@@ -9,24 +9,24 @@
 setl nodiff
 
 " untranslated message preceded by c-format or comment
-silent g/^#, c-format\n#/.d
-silent g/^#\..*\n#/.d
+silent g/^#, c-format\n#/.d _
+silent g/^#\..*\n#/.d _
 
 " c-format comments have no effect, the check.vim scripts checks it.
 " But they might still be useful?
-" silent g/^#, c-format$/d
+" silent g/^#, c-format$/d _
 
-silent g/^#[:~] /d
+silent g/^#[:~] /d _
 silent g/^#, fuzzy\(, .*\)\=\nmsgid ""\@!/.+1,/^$/-1s/^/#\~ /
 silent g/^msgstr"/s//msgstr "/
 silent g/^msgid"/s//msgid "/
 silent g/^msgstr ""\(\n"\)\@!/?^msgid?,.s/^/#\~ /
 
 " Comments only useful for the translator
-silent g/^#\. /d
+silent g/^#\./d _
 
 " clean up empty lines
-silent g/^\n\n\n/.d
+silent g/^\n\n\n/.d _
 silent! %s/\n\+\%$//
 
 if s:was_diff