doc: slight update of the package_state plugin docs

Relates: #1393

Author: praiskup

docs/Plugin-PackageState.md

@@ -3,7 +3,7 @@ layout: default
 title: Plugin PackageState
 ---
 
-This plugin dumps out two lists of pkgs into result dir:
+This plugin optionally dumps additional metadata files into the result dir:
 * A list of all available pkgs + repos + other data. This file is named `available_pkgs.log`. This file is not created if you run mock with `--offline` option.
 * A list of all installed pkgs + repos + other data. This file is name `installed_pkgs.log`.
 
@@ -13,11 +13,13 @@ Format of `installed_pkgs.log` file is:
 
 ## Configuration
 
-The Package_state plugin is disabled and can be enabled by:
+The Package_state plugin is enabled by default.
 
     # in version 1.2.18 and older the default was False
     config_opts['plugin_conf']['package_state_enable'] = True
 
+The following sub-options may be turned off/on:
+
     config_opts['plugin_conf']['package_state_opts'] = {}
     config_opts['plugin_conf']['package_state_opts']['available_pkgs'] = False
     config_opts['plugin_conf']['package_state_opts']['installed_pkgs'] = True