doc: add function "register" in the plugin API reference

doc/en/weechat_plugin_api.en.adoc

@@ -273,6 +273,29 @@ For each function, we give:
 * C example,
 * example in Python script (syntax for other scripting languages is similar).
 
+[[registering]]
+=== Registering
+
+Functions to register a script: used only by scripting API, not the C API.
+
+==== register
+
+Register the script.
+
+For more information, see the
+link:weechat_scripting.en.html#register_function[WeeChat scripting guide].
+
+Script (Python):
+
+[source,python]
+----
+# prototype
+weechat.register(name, author, version, license, description, shutdown_function, charset)
+----
+
+[NOTE]
+This function is not available in the C API.
+
 [[plugins]]
 === Plugins
 

doc/fr/weechat_plugin_api.fr.adoc

@@ -280,6 +280,31 @@ Pour chaque fonction, on donne :
 * un exemple en script Python (la syntaxe pour les autres langages de script est
   similaire).
 
+// TRANSLATION MISSING
+[[registering]]
+=== Enregistrement
+
+Functions pour enregistrer un script : utilisées seulement par l'API script,
+pas l'API C.
+
+==== register
+
+Enregistrer le script.
+
+Pour plus d'informations, voir le
+link:weechat_scripting.fr.html#register_function[Guide pour scripts WeeChat].
+
+Script (Python) :
+
+[source,python]
+----
+# prototype
+weechat.register(name, author, version, license, description, shutdown_function, charset)
+----
+
+[NOTE]
+Cette fonction n'est pas disponible dans l'API C.
+
 [[plugins]]
 === Extensions
 

doc/it/weechat_plugin_api.it.adoc

@@ -294,6 +294,30 @@ Per ogni funzione, viene fornita:
 * esempio nello script Python (la sintassi è simile per gli altri linguaggi di
   scripting).
 
+// TRANSLATION MISSING
+[[registering]]
+=== Registering
+
+Functions to register a script: used only by scripting API, not the C API.
+
+==== register
+
+Register the script.
+
+For more information, see the
+link:weechat_scripting.it.html#register_function[WeeChat scripting guide].
+
+Script (Python):
+
+[source,python]
+----
+# prototype
+weechat.register(name, author, version, license, description, shutdown_function, charset)
+----
+
+[NOTE]
+This function is not available in the C API.
+
 [[plugins]]
 === Plugin
 

doc/ja/weechat_plugin_api.ja.adoc

@@ -281,6 +281,30 @@ weechat_plugin_end (struct t_weechat_plugin *plugin)
 * C 言語での使用例、
 * Python スクリプトでの使用例 (他のスクリプト言語を使う場合も文法は似ています)。
 
+// TRANSLATION MISSING
+[[registering]]
+=== Registering
+
+Functions to register a script: used only by scripting API, not the C API.
+
+==== register
+
+Register the script.
+
+For more information, see the
+link:weechat_scripting.ja.html#register_function[WeeChat scripting guide].
+
+スクリプト (Python) での使用例:
+
+[source,python]
+----
+# プロトタイプ
+weechat.register(name, author, version, license, description, shutdown_function, charset)
+----
+
+[NOTE]
+This function is not available in the C API.
+
 [[plugins]]
 === プラグイン