Running a spell checker on the whole solution revealed a couple more
typos. This fixes all of those (although internal // line comments are
mostly left alone).
Additionally, convert a very few string.Format occurrences to the pre-
dominant .FormatWith pattern and fix some incorrect message strings.
If the JSON contained empty object "{}" for a byte[] property, the `JsonReader` ended up trying to read the object content despite the fact that the content didn't exist. This caused a null reference exception.
The fix ensures the value exists before trying to read it. If the value doesn't exist, the execution ends up in "Unexpected token" exception with way more informative error message.