Fix build.cmd help text (#3197)

build.cmd

@@ -37,10 +37,10 @@ echo.    build.cmd coreclr          (build compiler for .NET Core)
 echo.    build.cmd vs               (build Visual Studio IDE Tools)
 echo.    build.cmd all              (build everything)
 echo.    build.cmd test             (build and test default targets)
-echo.    build.cmd net40 test       (build and test net40)
-echo.    build.cmd coreclr test     (build and test net40)
-echo.    build.cmd vs test          (build and test net40)
-echo.    build.cmd all test         (build and test net40)
+echo.    build.cmd net40 test       (build and test compiler for .NET Framework)
+echo.    build.cmd coreclr test     (build and test compiler for .NET Core)
+echo.    build.cmd vs test          (build and test Visual Studio IDE Tools)
+echo.    build.cmd all test         (build and test everything)
 echo.    build.cmd nobuild test include Conformance (run only tests marked with Conformance category)
 echo.    build.cmd nobuild test include Expensive (run only tests marked with Expensive category)
 echo.