<effect> argument in /effect does not show clear in help syntax

When typing /help effect or just /effect, the game brings up the correct syntax in the chat, which reads:

/effect <player> <effect> [seconds] [amplifier] [hideParticles]

The <effect> argument also has another option, which is 'clear':

/effect <player> clear

which will clear all of their effects.
This option is not shown in the help syntax, and this other option should be shown.