patch 8.2.1375: Vim9: method name with digit not accepted

Problem:    Vim9: method name with digit not accepted.
Solution:   Use eval_isnamec() instead of eval_isnamec1(). (closes #6613)

src/version.c

@@ -754,6 +754,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1375,
 /**/
     1374,
 /**/