Issue #1977054 by ebargtuo, dooug: Make docs for language API callbacks match the code

includes/language.inc

@@ -78,7 +78,7 @@ define('LANGUAGE_NEGOTIATION_DEFAULT', 'language-default');
  * function mymodule_language_negotiation_info_alter(&$negotiation_info) {
  *   // Replace the core function with our own function.
  *   module_load_include('language', 'inc', 'language.negotiation');
- *   $negotiation_info[LANGUAGE_NEGOTIATION_URL]['callbacks']['negotiation'] = 'mymodule_from_url';
+ *   $negotiation_info[LANGUAGE_NEGOTIATION_URL]['callbacks']['language'] = 'mymodule_from_url';
  *   $negotiation_info[LANGUAGE_NEGOTIATION_URL]['file'] = drupal_get_path('module', 'mymodule') . '/mymodule.module';
  * }
  *
@@ -94,7 +94,6 @@ define('LANGUAGE_NEGOTIATION_DEFAULT', 'language-default');
  *   }
  *   return $langcode;
  * }
- * ?>
  * @endcode
  *
  * For more information, see

modules/system/language.api.php

@@ -118,11 +118,11 @@ function hook_language_types_info_alter(array &$language_types) {
  *     will be available for all the configurable language types.
  *   - callbacks: An associative array of functions that will be called to
  *     perform various tasks. Possible elements are:
- *     - negotiation: (required) Name of the callback function that determines
- *       the language value.
- *     - language_switch: (optional) Name of the callback function that
- *       determines links for a language switcher block associated with this
- *       provider. See language_switcher_url() for an example.
+ *     - language: (required) Name of the callback function that determines the
+ *       language value.
+ *     - switcher: (optional) Name of the callback function that determines
+ *       links for a language switcher block associated with this provider. See
+ *       language_switcher_url() for an example.
  *     - url_rewrite: (optional) Name of the callback function that provides URL
  *       rewriting, if needed by this provider.
  *   - file: The file where callback functions are defined (this file will be