patch 8.0.0328: the "zero count" error doesn't have a number

Problem:    The "zero count" error doesn't have a number. (Hirohito Higashi)
Solution:   Give it a number and be more specific about the error.
diff --git a/src/globals.h b/src/globals.h
index 0b6abb0..f3e5155 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -1581,7 +1581,7 @@
 EXTERN char_u e_winwidth[]	INIT(= N_("E592: 'winwidth' cannot be smaller than 'winminwidth'"));
 #endif
 EXTERN char_u e_write[]		INIT(= N_("E80: Error while writing"));
-EXTERN char_u e_zerocount[]	INIT(= N_("Zero count"));
+EXTERN char_u e_zerocount[]	INIT(= N_("E939: Positive count required"));
 #ifdef FEAT_EVAL
 EXTERN char_u e_usingsid[]	INIT(= N_("E81: Using <SID> not in a script context"));
 #endif