Angband added something like this in the 2000s, and all the recent variants include equivalent features. It's somewhat more useful in variants like Sil where the character-building process involves choosing specific skills to learn; in vanilla angband it's more indicative of whether the player likes to dive aggressively or explore thouroughly.
These systems, as well as automatically recording level-ups, slain unique monsters, found artefacts, and (in Sil) skills learnt, also allow the player to insert custom notes.
Wouldn't be surprised if Crawl has something like this?