Merge pull request #19246 from jtattermusch/csharp_doc_nits

C# docs improvements.

src/csharp/BUILD-INTEGRATION.md

@@ -355,3 +355,24 @@ Unless explicitly set, will follow `OutputDir` for any given file.
 
 * __Access__  
 Sets generated class access on _both_ generated message and gRPC stub classes.
+
+`grpc_csharp_plugin` command line options
+---------
+
+Under the hood, the `Grpc.Tools` build integration invokes the `protoc` and `grpc_csharp_plugin` binaries
+to perform code generation. Here is an overview of the available `grpc_csharp_plugin` options:
+
+| Name            | Default   | Synopsis                                                 |
+|---------------- |-----------|----------------------------------------------------------|
+| no_client       | off       | Don't generate the client stub                           |
+| no_server       | off       | Don't generate the server-side stub                      |
+| internal_access | off       | Generate classes with "internal" visibility              |
+| lite_client     | off       | Generate client stubs that inherit from "LiteClientBase" |
+
+Note that the protocol buffer compiler has a special commandline syntax for plugin options.
+Example:
+```
+protoc --plugin=protoc-gen-grpc=grpc_csharp_plugin --csharp_out=OUT_DIR \
+    --grpc_out=OUT_DIR --grpc_opt=lite_client,no_server \
+    -I INCLUDE_DIR foo.proto
+```

src/csharp/README.md

@@ -17,20 +17,20 @@ PREREQUISITES
 When using gRPC C# under .NET Core you only need to [install .NET Core](https://www.microsoft.com/net/core).
 
 In addition to that, you can also use gRPC C# with these runtimes / IDEs
-- Windows: .NET Framework 4.5+, Visual Studio 2013, 2015, 2017, Visual Studio Code
+- Windows: .NET Framework 4.5+, Visual Studio 2013 or newer, Visual Studio Code
-- Linux: Mono 4+, Visual Studio Code, MonoDevelop 5.9+ 
+- Linux: Mono 4+, Visual Studio Code
-- Mac OS X: Mono 4+, Visual Studio Code, Xamarin Studio 5.9+
+- Mac OS X: Mono 4+, Visual Studio Code, Visual Studio for Mac
 
 HOW TO USE
 --------------
 
 **Windows, Linux, Mac OS X**
 
-- Open Visual Studio / MonoDevelop / Xamarin Studio and start a new project/solution (alternatively, you can create a new project from command line with `dotnet` SDK)
+- Open Visual Studio and start a new project/solution (alternatively, you can create a new project from command line with `dotnet` SDK)
 
 - Add the [Grpc](https://www.nuget.org/packages/Grpc/) NuGet package as a dependency (Project options -> Manage NuGet Packages). 
 
-- To be able to generate code from Protocol Buffer (`.proto`) file definitions, add the [Grpc.Tools](https://www.nuget.org/packages/Grpc.Tools/) NuGet package that contains Protocol Buffers compiler (_protoc_) and the gRPC _protoc_ plugin.
+- To be able to generate code from Protocol Buffer (`.proto`) file definitions, add the [Grpc.Tools](https://www.nuget.org/packages/Grpc.Tools/) NuGet package which provides [code generation integrated into your build](BUILD-INTEGRATION.md).
 
 **Xamarin.Android and Xamarin.iOS (Experimental only)**