Abbreviations that are a subset of others are eaten

For instance: the leading `g` in `gph` will be eaten by a `g` abbreviation.

A possible fix is to allow a time period for abbreviations to complete. For instance, `gph` will resolve after 500ms rather than `g` resolving instantly.

Reproduce the abbreviation behavior with `gph`, confirming that the leading `g` abbreviation is consumed before the longer abbreviation can resolve. Trace the abbreviation-handling entry point and determine how completion is currently triggered; done means `gph` resolves as a whole while standalone `g` still works, with behavior verified by a regression check.

Written by the indexing model from the issue text.