patch 9.0.1266: error for space before ": type" is inconsistent

Problem:    Error for space before ": type" is inconsistent.
Solution:   Give E1059 in more places. (closes #11868)
diff --git a/src/evalvars.c b/src/evalvars.c
index 68df1cb..0665436 100644
--- a/src/evalvars.c
+++ b/src/evalvars.c
@@ -1363,8 +1363,8 @@
 
     if (include_type && vim9)
     {
-	if (*end == ':')
-	    end = skip_type(skipwhite(end + 1), FALSE);
+	if (*skipwhite(end) == ':')
+	    end = skip_type(skipwhite(skipwhite(end) + 1), FALSE);
     }
     return end;
 }