readme fix

Author: DannyBen

README.md

@@ -204,7 +204,7 @@ command and subcommands (under the `commands` definition).
 `help`     | The header text to display when using `--help`. This option can have multiple lines. In this case, the first line will be used as summary wherever appropriate.
 `version`  | The string to display when using `--version`. *Applicable only in the main command*.
 `default`  | Setting this to `true` on any command, will cause any unrecognized command line to be passed to this command. *Applicable only in subcommands*.
-`extensible` | Specify that this command can be [externally extended](#extensible-commands). *Applicable only in the main command*.
+`extensible` | Specify that this command can be [externally extended](#extensible-scripts). *Applicable only in the main command*.
 `examples` | Specify an array of examples to show when using `--help`. Each example can have multiple lines.
 `environment_variables` | Specify an array of [environment variables](#environment-variable-options) needed by your script. 
 `commands` | Specify the array of [commands](#command-options). Each command will have its own args and flags. Note: if `commands` is provided, you cannot specify flags or args at the same level.