Include reason within WSCloseCode

[swhitty]

Aligning within HTTPStatusCode, WSCloseCode now includes the reason within the structure making it easier to pass around:

public struct WSCloseCode: Sendable, Hashable {
    public var code: UInt16
    public var reason: String

    public init(_ code: UInt16) {
        self.code = code
        self.reason = ""
    }
    public init(_ code: UInt16, reason: String) {
        self.code = code
        self.reason = reason
    }
}

Additionally closes the stream when a close message is sent to client

[codecov]

Codecov Report

Attention: Patch coverage is 88.88889% with 3 lines in your changes missing coverage. Please review.

Project coverage is 94.58%. Comparing base (7d98b0c) to head (9cd8705).

✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
FlyingFox/Sources/WebSocket/WSHandler.swift	82.35%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #146      +/-   ##
==========================================
+ Coverage   94.52%   94.58%   +0.06%     
==========================================
  Files          62       62              
  Lines        4015     4023       +8     
==========================================
+ Hits         3795     3805      +10     
+ Misses        220      218       -2     

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