Add host: parameter to PreviewAction.init

Now that `PreviewServer` requires an explicit host name, we should
require one here too instead of hardcoding `localhost`.

Author: tomstuart

Sources/SwiftDocCUtilities/Action/Actions/PreviewAction.swift

@@ -53,6 +53,7 @@ public final class PreviewAction: Action, RecreatingContext {
 
     var logHandle = LogHandle.standardOutput
 
+    let host: String
     let port: Int
 
     var convertAction: ConvertAction
@@ -75,6 +76,7 @@ public final class PreviewAction: Action, RecreatingContext {
     /// Creates a new preview action from the given parameters.
     ///
     /// - Parameters:
+    ///   - host: The host name used by the preview server.
     ///   - port: The port number used by the preview server.
     ///   - convertAction: The action used to convert the documentation bundle before preview.
     ///   On macOS, this action will be reused to convert documentation each time the source is modified.
@@ -84,6 +86,7 @@ public final class PreviewAction: Action, RecreatingContext {
     ///     is performed.
     /// - Throws: If an error is encountered while initializing the documentation context.
     public init(
+        host: String,
         port: Int,
         createConvertAction: @escaping () throws -> ConvertAction,
         workspace: DocumentationWorkspace = DocumentationWorkspace(),
@@ -95,6 +98,7 @@ public final class PreviewAction: Action, RecreatingContext {
         }
 
         // Initialize the action context.
+        self.host = host
         self.port = port
         self.createConvertAction = createConvertAction
         self.convertAction = try createConvertAction()
@@ -108,13 +112,14 @@ public final class PreviewAction: Action, RecreatingContext {
     @available(*, deprecated, message: "TLS support has been removed.")
     public convenience init(
         tlsCertificateKey: URL?, tlsCertificateChain: URL?, serverUsername: String?,
-        serverPassword: String?, port: Int,
+        serverPassword: String?, host: String, port: Int,
         createConvertAction: @escaping () throws -> ConvertAction,
         workspace: DocumentationWorkspace = DocumentationWorkspace(),
         context: DocumentationContext? = nil,
         printTemplatePath: Bool = true) throws
     {
         try self.init(
+            host: host,
             port: port,
             createConvertAction: createConvertAction,
             workspace: workspace,
@@ -165,15 +170,15 @@ public final class PreviewAction: Action, RecreatingContext {
             print(String(repeating: "=", count: 40), to: &logHandle)
             var components = URLComponents()
             components.scheme = "http"
-            components.host = "localhost"
+            components.host = host
             components.port = port
             if let previewURL = components.url {
                 print("Starting Local Preview Server", to: &logHandle)
                 printPreviewAddresses(base: previewURL)
                 print(String(repeating: "=", count: 40), to: &logHandle)
             }
 
-            let to: PreviewServer.Bind = bindServerToSocketPath.map { .socket(path: $0) } ?? .localhost(host: "localhost", port: port)
+            let to: PreviewServer.Bind = bindServerToSocketPath.map { .socket(path: $0) } ?? .localhost(host: host, port: port)
             servers[serverIdentifier] = try PreviewServer(contentURL: convertAction.targetDirectory, bindTo: to, logHandle: &logHandle)
 
             // When the user stops docc - stop the preview server first before exiting.

Sources/SwiftDocCUtilities/ArgumentParsing/ActionExtensions/PreviewAction+CommandInitialization.swift

@@ -24,6 +24,7 @@ extension PreviewAction {
     {
         // Initialize the `PreviewAction` from the options provided by the `Preview` command
         try self.init(
+            host: "localhost",
             port: previewOptions.port,
             createConvertAction: {
                 try ConvertAction(