zsh: tone down error feedback in prompt
zsh: tone down error feedback in prompt

Yellow fg instead of bg. Looks reasonable in both Ocean dark and light.

wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent