patch 8.0.0726: translations cleanup script is too conservative

Problem:    Translations cleanup script is too conservative.
Solution:   Also delete untranslated messages.
diff --git a/src/version.c b/src/version.c
index 1513ee5..85814a4 100644
--- a/src/version.c
+++ b/src/version.c
@@ -770,6 +770,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    726,
+/**/
     725,
 /**/
     724,