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/arabic.c b/src/arabic.c
index efc6aa6..f64dab2 100644
--- a/src/arabic.c
+++ b/src/arabic.c
@@ -163,8 +163,6 @@
 
 #define a_BYTE_ORDER_MARK		0xfeff
 
-#define ARRAY_SIZE(a)		(sizeof(a) / sizeof((a)[0]))
-
 /*
  * Find the struct achar pointer to the given Arabic char.
  * Returns NULL if not found.
@@ -175,7 +173,7 @@
     int h, m, l;
 
     // using binary search to find c
-    h = ARRAY_SIZE(achars);
+    h = ARRAY_LENGTH(achars);
     l = 0;
     while (l < h)
     {