Merge pull request #21835 from longkb/remove_redundance_words

Fix some spelling errors in comment

src/csharp/Grpc.Core.Api/CallCredentials.cs

@@ -30,7 +30,7 @@ namespace Grpc.Core
     public abstract class CallCredentials
     {
         /// <summary>
-        /// Composes multiple multiple <c>CallCredentials</c> objects into
+        /// Composes multiple <c>CallCredentials</c> objects into
         /// a single <c>CallCredentials</c> object.
         /// </summary>
         /// <param name="credentials">credentials to compose</param>

src/csharp/Grpc.Core.Api/CallOptions.cs

@@ -112,7 +112,7 @@ namespace Grpc.Core
         }
 
         /// <summary>
-        /// If <c>true</c> and and channel is in <c>ChannelState.TransientFailure</c>, the call will attempt waiting for the channel to recover
+        /// If <c>true</c> and channel is in <c>ChannelState.TransientFailure</c>, the call will attempt waiting for the channel to recover
         /// instead of failing immediately (which is the default "FailFast" semantics).
         /// Note: experimental API that can change or be removed without any prior notice.
         /// </summary>

src/csharp/Grpc.Core/Internal/UnmanagedLibrary.cs

@@ -217,7 +217,7 @@ namespace Grpc.Core.Internal
         }
 
         /// <summary>
-        /// On Linux systems, using using dlopen and dlsym results in
+        /// On Linux systems, using dlopen and dlsym results in
         /// DllNotFoundException("libdl.so not found") if libc6-dev
         /// is not installed. As a workaround, we load symbols for
         /// dlopen and dlsym from the current process as on Linux