Chainable require hook

Changes for 0.013 - 2023-04-22

• Add hook: source::test::code.
• [doc] Tweak document for source::test::str hook.

Perl extension for generate Russian wording of numerals from the natural numbers and 0 (zero).

Changes for 0.07

• added a new subroutines -- case_endings(), spelled_out_number();
• expanded call context (SCALAR, LIST or VOID) of num2cardinal();
• expanded 'epilog' option of num2cardinal();
• expanded 'alt' option of num2cardinal();
• added optimizations;
• added new tests and increased test coverage;
• typos fixed;
• POD, README, and Makefile.PL revised.

Yet another NoteBook widget

Changes for 0.03

• fixed highlightthickness of tab buttons (set it to 0) fixed deep recursion issue on UpdateTabs