minor improvements, typos, etc.

content/docs/macros/MV_INDEX_TO_NUM.md

@@ -14,19 +14,20 @@ will replace all instances of named indexes with a unique number constant.
 ## Valid Usage
 
 ```lua
-local foo = MV_INDEX_TO_NUM({total = 0})
+local foo = MV_INDEX_TO_NUM({total = 0, b = 2})
 for i = 1, 10 do
   foo.total = foo.total + i
 end
-return foo.total
+return foo.total + foo.b
 ```
 
 turns into:
 
 ```lua
-local a={[19314]=0}
+-- note that the order of the indexes has been changed as well
+local a={[24453]=2,[19314]=0}
 for b=1,10 do
     a[19314]=a[19314]+b
 end
-return a[19314]
+return a[19314] + a[24453]
 ```