Reword code comments in plain technical language

Comments only, no code changes. Replaces vague or personified phrasing
with explicit statements of what the code does and why, uses bullet
lists for multi-case behavior, and fixes the settings path in
WindowSettings.h (~/.config/sloposk/sloposk.conf).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/input/DeadKeys.cpp

@@ -51,7 +51,8 @@ QString DeadKeys::press(quint32 deadKeysym)
         return composed;
     }
     case XKB_COMPOSE_CANCELLED: {
-        // No sequence goes on like this: type the old accents, start anew.
+        // No compose sequence continues with this key: flush the pending accents
+        // and start a new sequence.
         const QString accents = m_pending;
         cancel();
         return accents + press(deadKeysym);