The default behaviour should probably be mentioned here, maybe:

"Turns underscores into spaces, and strips a trailing '_id' if present. Also capitalizes the first word by default."

then later...

"The capitalization behaviour can be changed by ..."

Probably not the best possible way to say this, but my point is that it seems easier to read if we point out the default upfront (since that's how most people will use this) and point out what can be changed (+how) later.