refactor: remove smaller commented-out alternative branches

Four dead-code blocks deleted, all of them commented-out
alternative implementations next to the live versions:

- 5-line commented (and (>= quality 4) ...) cond branch in the
  SM5 scheduler
- 6-line commented (loop do (re-search-forward ...)) alternative
  in present-multicloze-hide-n
- 4-line commented unless-error guards at the top of entry-f
- 3-line commented (:tomorrow ...) case branch in
  map-entry-function

Prose commentary kept (license, package overview, recent-fix
explanations).  Pure deletion, no behavior change.

0 files changed, 0 insertions, 0 deletions