“it’s called a spell checker”
I’ve seen it both ways.
Check this out: (abridged version)
“An Owed to the Spelling Checker”
by Jerrold H. Zar
I have a spelling checker.
It came with my PC.
It plane lee marks four my revue
Miss steaks aye can knot sea.
Eye ran this poem threw it,
Your sure reel glad two no.
Its vary polished in it’s weigh,
My checker tolled me sew.