Remove experimental comment from client interceptors (#3948)

interceptor.go

@@ -25,25 +25,41 @@ import (
 // UnaryInvoker is called by UnaryClientInterceptor to complete RPCs.
 type UnaryInvoker func(ctx context.Context, method string, req, reply interface{}, cc *ClientConn, opts ...CallOption) error
 
-// UnaryClientInterceptor intercepts the execution of a unary RPC on the client. invoker is the handler to complete the RPC
-// and it is the responsibility of the interceptor to call it.
+// UnaryClientInterceptor intercepts the execution of a unary RPC on the client.
+// Unary interceptors can be specified as a DialOption, using
+// WithUnaryInterceptor() or WithChainUnaryInterceptor(), when creating a
+// ClientConn. When a unary interceptor(s) is set on a ClientConn, gRPC
+// delegates all unary RPC invocations to the interceptor, and it is the
+// responsibility of the interceptor to call invoker to complete the processing
+// of the RPC.
 //
-// Experimental
+// method is the RPC name. req and reply are the corresponding request and
+// response messages. cc is the ClientConn on which the RPC was invoked. invoker
+// is the handler to complete the RPC and it is the responsibility of the
+// interceptor to call it. opts contain all applicable call options, including
+// defaults from the ClientConn as well as per-call options.
 //
-// Notice: This type is EXPERIMENTAL and may be changed or removed in a
-// later release.
+// The returned error must be compatible with the status package.
 type UnaryClientInterceptor func(ctx context.Context, method string, req, reply interface{}, cc *ClientConn, invoker UnaryInvoker, opts ...CallOption) error
 
 // Streamer is called by StreamClientInterceptor to create a ClientStream.
 type Streamer func(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, opts ...CallOption) (ClientStream, error)
 
-// StreamClientInterceptor intercepts the creation of ClientStream. It may return a custom ClientStream to intercept all I/O
-// operations. streamer is the handler to create a ClientStream and it is the responsibility of the interceptor to call it.
+// StreamClientInterceptor intercepts the creation of a ClientStream. Stream
+// interceptors can be specified as a DialOption, using WithStreamInterceptor()
+// or WithChainStreamInterceptor(), when creating a ClientConn. When a stream
+// interceptor(s) is set on the ClientConn, gRPC delegates all stream creations
+// to the interceptor, and it is the responsibility of the interceptor to call
+// streamer.
 //
-// Experimental
+// desc contains a description of the stream. cc is the ClientConn on which the
+// RPC was invoked. streamer is the handler to create a ClientStream and it is
+// the responsibility of the interceptor to call it. opts contain all applicable
+// call options, including defaults from the ClientConn as well as per-call
+// options.
 //
-// Notice: This type is EXPERIMENTAL and may be changed or removed in a
-// later release.
+// StreamClientInterceptor may return a custom ClientStream to intercept all I/O
+// operations. The returned error must be compatible with the status package.
 type StreamClientInterceptor func(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, streamer Streamer, opts ...CallOption) (ClientStream, error)
 
 // UnaryServerInfo consists of various information about a unary RPC on