app-chooser: update docs

gtk/gtkappchooserdialog.c

@@ -660,9 +660,16 @@ gtk_app_chooser_dialog_class_init (GtkAppChooserDialogClass *klass)
 
   g_object_class_override_property (gobject_class, PROP_CONTENT_TYPE, "content-type");
 
+  /**
+   * GtkAppChooserDialog:gfile:
+   *
+   * The GFile used by the #GtkAppChooserDialog.
+   * The dialog's #GtkAppChooserWidget content type will be guessed from the
+   * file, if present.
+   */
   pspec = g_param_spec_object ("gfile",
                                P_("GFile"),
-                               P_("The GFile used by the open with dialog"),
+                               P_("The GFile used by the app chooser dialog"),
                                G_TYPE_FILE,
                                G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE |
                                G_PARAM_STATIC_STRINGS);