[tepl] LanguageChooser: add TODO comment

[Sébastien Wilmet <swilmet src gnome org>]

commit c5842ecb2b7828d34a6b2f33de508a099ccdfdce
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Mon Nov 9 13:28:12 2020 +0100

    LanguageChooser: add TODO comment

 tepl/tepl-language-chooser.c | 9 +++++++++
 1 file changed, 9 insertions(+)
---
diff --git a/tepl/tepl-language-chooser.c b/tepl/tepl-language-chooser.c
index 9418617..f487111 100644
--- a/tepl/tepl-language-chooser.c
+++ b/tepl/tepl-language-chooser.c
@@ -33,6 +33,15 @@
  * repeating the API.
  */
 
+/* TODO: implement a TeplLanguageChooserButton class.
+ * For TeplLanguageChooserButton, it would probably be more convenient to have
+ * two properties instead of the ::language-activated signal: the :language and
+ * :language-id properties (the :language-id property would be useful to bind it
+ * to a GSettings key).
+ * A TeplLanguageChooserButton would be useful to choose the default language
+ * for new files, by adding the button in a preferences dialog.
+ */
+
 enum
 {
        SIGNAL_LANGUAGE_ACTIVATED,