"upon" is not suggested by the spellchecker for the misspelling "apon"

I'm thinking we could use some data-driven engine in a spellchecker redesign.

It would involve the spellchecker suggestions changing from additive scoring to weighted scoring, and a separate tool that finds good sets of weights for various letters, sequences, contexts. It would have a set of misspellings and their true corrections and run over them all with tweaks to the weights until a maximum number of true corrections are found by those weights.

This could be done by AI or by manually coded data-analysis routines.

No files, tests, or entry points are named. Start by reproducing the "apon" suggestion case and tracing the current spellchecker scoring; done would require a decided redesign that ranks "upon" correctly and demonstrates improved corrections across a defined set of misspellings.

Written by the indexing model from the issue text.