remove all references to wrangler.toml

[dario-piotrowicz]

Since we're moving to promoting the json format (cloudflare/workers-sdk#7676) instead of toml for the wrangler config I went back to the Cloudflare docs here to remove all references to wrangler.toml

Note

I didn't remove those from the 0.2 section as I think it should be kept there.

Although I would actually prefer to get rid of the 0.2 section altogether, especially since we had this section+migration for a while (devs that were on 0.2 would most likely have already migrated) and the package itself is still in beta/experimental anyways.
@vicb any plan/idea if/when we can remove the 0.2 docs?

Note

As you can see in this PR my preference when referring to the config file is to generically call it something like wrangler configuration file instead of directly wrangler.json I think that that's just more accurate and future proof (if for example we later decide to default to wrangler.jsonc for example, or even to a wrangler.config.ts, all the generic references to the file would still be correct and wouldn't need to be updated)