add automata and compiler construction

As @alanduan mentioned in CPyUG mail groups, automata and compiler construction are some other important topics in Computer Science.

The issue does not name files, sections, or entry points. Start by inspecting the repository's notes structure and existing topic conventions, then determine how automata and compiler construction should fit; done should include substantive coverage of both topics consistent with the rest of the notes.

Written by the indexing model from the issue text.