message: Update mentions to codegen configuration key in changelog
  As well as in one error message.
  The key is `codegen`, not `codegenConfig`.
diff: @@ -47,7 +47,7 @@ private sealed class UnsupportedConstraintMessageKind {
  if (canBeIgnored) {
  msg += """
  If you want to go ahead and generate the server SDK ignoring unsupported constraint traits, set the key `ignoreUnsupportedConstraints`
  - inside the `runtimeConfig.codegenConfig` JSON object in your `smithy-build.json` to `true`."""
  + inside the `runtimeConfig.codegen` JSON object in your `smithy-build.json` to `true`."""
  }
  return msg.trimIndent().replace("\n", " ")
  }
  