fix(3c-ii): address Copilot review on PR #12

- ServerResolver ctor XML doc: 'servers' is the IServerService, not a list.
- Rename ServerResolver test DefaultsToSingleServer_IgnoringArg ->
  DefaultsToSingleServer_WhenNoArg: it passes a null arg, so the name now
  matches what it covers. (The single-server + explicit-non-matching-arg ->
  'unknown' path is already covered by ReturnsUnknownError_WhenArgNotRegistered.)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: HandyS11

src/RustPlusBot.Features.Commands/Servers/ServerResolver.cs

@@ -4,7 +4,7 @@
 namespace RustPlusBot.Features.Commands.Servers;
 
 /// <summary>Picks the target server for a slash command from an optional (autocompleted) server argument.</summary>
-/// <param name="servers">The guild's server list.</param>
+/// <param name="servers">The server service used to list the guild's servers.</param>
 /// <param name="localizer">Resolves the error messages.</param>
 internal sealed class ServerResolver(IServerService servers, ICommandLocalizer localizer)
 {

tests/RustPlusBot.Features.Commands.Tests/Servers/ServerResolverTests.cs

@@ -31,7 +31,7 @@ public async Task ReturnsError_WhenNoServers()
     }
 
     [Fact]
-    public async Task DefaultsToSingleServer_IgnoringArg()
+    public async Task DefaultsToSingleServer_WhenNoArg()
     {
         var id = Guid.NewGuid();
         var r = await Build(Server(id, "Main")).ResolveAsync(1UL, null, "en", CancellationToken.None);