[Docs] Update length-tokenfilter.asciidoc
Made it clear what the numeric value of `Integer.MAX_VALUE`  is,
@@ -11,6 +11,6 @@ type:
|===========================================================
|Setting |Description
|`min` |The minimum number. Defaults to `0`.
-|`max` |The maximum number. Defaults to `Integer.MAX_VALUE`.
+|`max` |The maximum number. Defaults to `Integer.MAX_VALUE`, which is `2^31-1` or 2147483647.
|===========================================================
