Add docs

Author: gjcairo

Sources/GRPC/ClientConnection.swift

@@ -470,6 +470,7 @@ extension ClientConnection {
     public var debugChannelInitializer: (@Sendable (Channel) -> EventLoopFuture<Void>)?
 
     #if canImport(Network)
+    /// A closure allowing to customise the `NWParameters` used when establising a connection using NIOTransportServices.
     @available(macOS 10.14, iOS 12.0, watchOS 6.0, tvOS 12.0, *)
     public var nwParametersConfigurator: (
       @Sendable (NIOTSConnectionBootstrap) -> Void

Sources/GRPC/ConnectionPool/GRPCChannelPool.swift

@@ -320,7 +320,7 @@ extension GRPCChannelPool.Configuration {
       return configuration
     }
 
-    // TODO: write docs
+    /// A closure allowing to customise the `NWParameters` used when establising a connection using NIOTransportServices.
     @available(macOS 10.14, iOS 12.0, watchOS 6.0, tvOS 12.0, *)
     public var nwParametersConfigurator: (
       @Sendable (NIOTSConnectionBootstrap) -> Void

Sources/GRPC/Server.swift

@@ -391,6 +391,7 @@ extension Server {
     internal var serviceProvidersByName: [Substring: CallHandlerProvider]
 
     #if canImport(Network)
+    /// A closure allowing to customise the `NWParameters` used when establising a connection using NIOTransportServices.
     @available(macOS 10.14, iOS 12.0, watchOS 6.0, tvOS 12.0, *)
     public var nwParametersConfigurator: (
       @Sendable (NIOTSListenerBootstrap) -> Void