Update the format_number example

and add link to list of iso language codes

resources/function_help/json/format_number

@@ -5,7 +5,7 @@
   "description": "Returns a number formatted with the locale separator for thousands. Also truncates the decimal places to the number of supplied places.",
   "arguments": [ {"arg":"number","description":"number to be formatted"},
                  {"arg":"places","description":"integer representing the number of decimal places to truncate the string to."},
-                 {"arg":"language","optional":true,"description":"language (lowercase, two- or three-letter, ISO 639 language code) used to format the number into a string"}],
-  "examples": [ { "expression":"format_number(10000000.332,2)", "returns":"'10,000,000.33'"}
-  ]
+                 {"arg":"language","optional":true,"description":"language (lowercase, two- or three-letter, <a href='https://en.wikipedia.org/wiki/List_of_ISO_639-1_codes'>ISO 639 language code</a>) used to format the number into a string"}],
+  "examples": [ { "expression":"format_number(10000000.332,2)", "returns":"'10,000,000.33'"},
+                { "expression":"format_number(10000000.332,2,'fr')", "returns":"'10 000 000,33'"}]
 }