extension using --merge-sources

I was under the impression that they should be broken out no matter what from #60 and personally think they should be. The only use case I can think of for merging schema-generated objects/paths would be for reference or other developer-meta purposes. While devs might also move files around, they will still have to be responsible for moving these extensions as well (split or merged).

Essentially, it splits the concerns of each file: Entities.swift for generated objects, Paths.swift for generated paths, and then each extension file is their own helper file. Additionally, the (default) naming scheme sorts them nicely into each section. We won't have to think further about that until I finish the filename template work.

#47

I don't think that this simple change in logic should worry about that until a consensus is reached there. I'll leave my thoughts on the issue.

I was under the impression that they should be broken out no matter wha

Doh, you are right.. I forgot that I even suggested that 😅 #60 (comment)

I don't think that this simple change in logic should worry about that until a consensus is reached there. I'll leave my thoughts on the issue.

Sure 👍

Let me just do some final tests of this change 👀 It's hard to review on GitHub as the diff freezes up my browser 😄

Please can you revert the rest of the changes to Snapshots.swift 🙏 Keep in mind that this diff is gigantic and barely loads in the browser so it makes it hard to efficiently review things 🙇

Its not worth changing it now, but my suggestion if we were to do this again would be to submit a pull request that switches --split for --merge-sources, but updates all the test fixtures that didn't use --split to use --merge-sources (and vice versa).. This would have helped us to be completely sure that the only other changes in output were related to moving the extensions since the diff would have been readable. We could then update all the fixtures to stop using --merge-sources in a separate PR where the diff is less important 🙏

Thanks again though for working on this! Will merge it once the checks finish ✅

Thanks again @LePips for the great contribution 🚀