New EventCode API

[cbs228]

Previous versions of the EventCode API had two problems:

1. The conversion from MessageHeader → EventCode was fallible, even though messages with unrecognized event codes should still be played.

2. Since each SAME event code was its own EventCode, it was not possible to separate the phenomenon from the severity.

This PR is a major overhaul of all enums used to decode SAME event codes.

Originator

• Improved detection of National Weather Service vs Environment Canada. The WeatherService enum variant is dropped.

• Rename Originator::as_str() to Originator::as_code_str() for clarity

• Support the "alternate" format code.

• Originator is no longer From<&str>. Instead, it should be constructed via Originator::from_org_and_call().

SignificanceLevel

• SignificanceLevel::from() constructs directly from significance code str. The conversion is now infallible.

  • A new SignificanceLevel::Unknown variant is returned when a significance level cannot be determined. It sorts higher than Warning.

  • The UnknownSignificanceLevel is no longer required and is removed.

• Renamed SignificanceLevel::as_str() → SignificanceLevel::as_code_str(). This method returns a one-character significance code.

• The following messages are upgraded to Statement:

  • ADR Administrative Message
  • NMN Network Message Notification

Phenomenon

• The enum of all the SAME events is renamed to Phenomenon.

• Phenomenon previously de-normalized into significance levels, like TornadoWatch and TornadoWarning, are represented as a single enum entry like Tornado.

• Phenomenon from the 2022 revision of NWSI 10-1712 and more Canadian codes are added:

  • EAN: Renamed to National Emergency Message
  • NAT: National Audible Test
  • NST: National Silent Test
  • FSW: Flash Freeze Warning
  • FZW: Freeze Warning
  • HLS: Hurricane Local Statement
  • SQW: Snow Squall Warning

• Add basic categories of Phenomenon

• Fix bad code entry for ADR (Administrative Message)

EventCode

• The EventCode is now a struct which represents the combination of a Phenomenon and a SignificanceLevel.

• EventCode no longer convert directly to static str. Formatting requires either Display or to_string(). The human-readable string output for each SAME event code is largely unchanged. Remove EventCode::as_display_str() and replace with as_display_string().

• The alternate formatter for EventCode now displays only the phenomenon, like Tornado, without the significance level

• EventCode are now Ord by their significance levels

• EventCode no longer convert back to their original SAME event code string. Use MessageHeader::event_str() instead.

This is an API-BREAKING change.