jsonAlternateNames

When reading JSON these are alternate names for each field. If null the field has no alternate name.

For reserved keywords in Kotlin or Java, a field like public are written as so although the generated field name is public_. We want to read in either form. As well, in proto3 fields declared in snake_case like customer_id are written in camelCase like customerId, but can be read in either form. We can use exclusive logic between the two cases because there's no keyword defined in snake_case. The alternate name will be absent if the field name isn't a keyword or if the snake and camel cases are the same, such as in single-word identifiers. Lastly, in order to deserialize camelCased field from proto2, we add a camelCase alternative if the jsonName doesn't already match it.