Review for consistent use of English

[robotlolita]

Parts of the codebase (API and documentation) use British English spelling, parts use US English (e.g.: core.lambda.partialise vs. core.adt.serialize). This is probably going to be confusing to people.

Should probably just move everything to US English since it's more familiar to people.

Alternatively, we could have aliases to support both, but that increases the API surface so id.

See https://github.com/origamitower/folktale/blob/master/ROADMAP.hs