Problem: doc/pending.txt was written before the undo stack, folds,
:Pending due, D mapping, and BufEnter reload were added. Several
entries were factually wrong (single-level undo, d vs D key,
:Pending undo listed as non-existent) and highlight group defaults
referenced stale hex colours.
Solution: correct all factual errors and add missing entries —
:Pending due command, :Pending undo command, zc/zo fold mappings,
PendingOverdue highlight group, semantic link defaults for all groups,
category fold docs, BufEnter auto-reload note, and multi-level undo
description.