Fix typo (#1559)

Author: guardrex

src/Microsoft.Extensions.Hosting.Abstractions/IHostLifetime.cs

@@ -9,7 +9,7 @@ namespace Microsoft.Extensions.Hosting
  public interface IHostLifetime
  {
  /// <summary>
- /// Called at the start of <see cref="IHost.StartAsync(CancellationToken)"/> which will wait until it's compete before
+ /// Called at the start of <see cref="IHost.StartAsync(CancellationToken)"/> which will wait until it's complete before
  /// continuing. This can be used to delay startup until signaled by an external event.
  /// </summary>
  Task WaitForStartAsync(CancellationToken cancellationToken);