Hooks:

  p10k-on-init (may be called while zle is active or not)
  p10k-on-pre-prompt (may be called while zle is active or not)
  p10k-on-post-prompt
  p10k-on-post-widget

Parameters accessible from all hooks:

  P9K_PROMPT=regular|instant
  P9K_TTY=old|new

Parameters accessible from p10k-on-post-widget:

  All regular zle parameters (WIDGET, BUFFER, CURSOR, etc.).
  P9K_COMMAND
  P9K_LASTCOMMAND
  P9K_LASTBUFFER
  P9K_LASTCURSOR

`P9K_LAST*` parameters are set if and only if this isn't the first p10k-on-post-widget call after p10k-on-init.

# TODO: call all hooks with user options