patch 8.2.5170: tiny issues

Problem:    Tiny issues.
Solution:   Tiny improvements.
diff --git a/src/vim.h b/src/vim.h
index 1e66d51..97ce639 100644
--- a/src/vim.h
+++ b/src/vim.h
@@ -1653,7 +1653,7 @@
 
 /*
  * defines to avoid typecasts from (char_u *) to (char *) and back
- * (vim_strchr() and vim_strrchr() are now in alloc.c)
+ * (vim_strchr() and vim_strrchr() are now in strings.c)
  */
 #define STRLEN(s)	    strlen((char *)(s))
 #define STRCPY(d, s)	    strcpy((char *)(d), (char *)(s))