A few more improvements

doc/command_line_tool.md

@@ -63,15 +63,10 @@ $ cmake -DgRPC_BUILD_TESTS=ON ../..
 Finally you can build the command line tool with the command:
 
 ```
+# run from cmake/build directory
 $ make grpc_cli
 ```
 
-To speed up compilation time on linux, you can use make with following flag:
-
-```
-$ make grpc_cli -j$(nproc)
-```
-
 The main file can be found at
 https://github.com/grpc/grpc/blob/master/test/cpp/util/grpc_cli.cc