patch 7.4.1820

Problem:    Removing language from help tags too often.
Solution:   Only remove @en when not needed. (Hirohito Higashi)

src/version.c

@@ -753,6 +753,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1820,
 /**/
     1819,
 /**/