Improve Documentation: Clarify "Flavor Text" Status Messages

DISABLE_NON_ESSENTIAL_MODEL_CALLS=1 disables "flavor text" but the documentation doesn't provide any information about what "flavor text" means or examples of it.

My goal is to disable the random (somewhat funny) messages Claude Code shows while working. For instance, the word "Creating" in :*Creating (90s 100 tokens esc to interrupt)"

I do not want to create an issue for that if this does it. On the other hand, I'd like to know what else I am disabling.