patch 8.2.2922: computing array length is done in various ways

Problem:    Computing array length is done in various ways.
Solution:   Use ARRAY_LENGTH everywhere. (Ken Takata, closes #8305)
diff --git a/src/gui_w32.c b/src/gui_w32.c
index 80a70e2..c1f823e 100644
--- a/src/gui_w32.c
+++ b/src/gui_w32.c
@@ -1627,7 +1627,7 @@
     /*
      * Try to look up a system colour.
      */
-    for (i = 0; i < sizeof(sys_table) / sizeof(sys_table[0]); i++)
+    for (i = 0; i < ARRAY_LENGTH(sys_table); i++)
 	if (STRICMP(name, sys_table[i].name) == 0)
 	    return GetSysColor(sys_table[i].color);
 
@@ -5077,7 +5077,7 @@
 /*
  * Parse the GUI related command-line arguments.  Any arguments used are
  * deleted from argv, and *argc is decremented accordingly.  This is called
- * when vim is started, whether or not the GUI has been started.
+ * when Vim is started, whether or not the GUI has been started.
  */
     void
 gui_mch_prepare(int *argc, char **argv)