fix: fix missing body field (#13)

[kjetilhartveit]

I thought transformType() used with reduce() is generally hard to understand so I might miss something(?), but as the body widget is usually string it should be covered by the next block statement if (typeof widget.type === "string") { .... This seems to fix the issue and the body is including in the generated types.

[kjetilhartveit]

Or, is this behavior "expected", as one is most likely storing the items as frontmatter files and when retrieving them the content is separated from the metadata? It was just unexpected for me as a first time user and not clear why body wasn't generated. I was expecting the types to fully reflect the config. If this is intentional behavior then it should be documented and preferably customizable?