* tta/C/main/node_name_normalization.c
(convert_to_normalized_internal): use the equivalent builtin command
obtained by calling element_builtin_data_cmd for checks and as
command_normalization_text index.  This is important if the element is
a user-defined @-command, such as a definfoenclosed command.  Report
by Hilmar Preusse and analysis by Gavin.
  https://mail.gnu.org/archive/html/bug-texinfo/2026-02/msg00110.html

* tta/perl/Makefile.tres, tta/perl/t/08misc_commands.t
(definfoenclose_command_on_section_line): test definfoenclose defined
command on section line.