`<ToolType>antlr-ng</ToolType>` doesn't work.

[kaby76]

When I perform testing on Windows/MSYS2, I get this:

$ cd single-antlr-ng/
01/14-04:59:40 /c/Users/Kenne/Documents/GitHub/Antlr4BuildTasks-current/_tests/single-antlr-ng
$ ls
Arithmetic.g4  ErrorListener.cs  Program.cs  single-antlr-ng.csproj  test.sh*
01/14-04:59:41 /c/Users/Kenne/Documents/GitHub/Antlr4BuildTasks-current/_tests/single-antlr-ng
$ dotnet build
Restore complete (1.1s)
  single-antlr-ng net10.0 failed with 3 error(s) (0.3s)
    C:\Users\Kenne\.nuget\packages\antlr4buildtasks\12.13.0\build\Antlr4BuildTasks.targets(142,9): error ANT02: Could not find antlr-ng. Please install it using 'npm install -g antlr-ng' or 'npm install --save-dev antlr-ng'.
    C:\Users\Kenne\.nuget\packages\antlr4buildtasks\12.13.0\build\Antlr4BuildTasks.targets(142,9): error ANT02: Cannot find antlr-ng, currently set to ''   at Antlr4.Build.Tasks.RunAntlrTool.Execute()
    C:\Users\Kenne\.nuget\packages\antlr4buildtasks\12.13.0\build\Antlr4BuildTasks.targets(142,9): error ANT02: The Antlr4 tool failed.

Build failed with 3 error(s) in 2.0s
01/14-04:59:50 /c/Users/Kenne/Documents/GitHub/Antlr4BuildTasks-current/_tests/single-antlr-ng
$

Notice I get the error message Could not find antlr-ng. Please install it using 'npm install -g antlr-ng' or 'npm install --save-dev antlr-ng'.

The central requirement of Antlr4BuildTasks is:

Never require anything. Download whatever you need because I am a novice; or, I don't want to be bothered setting up my environment; or, I don't want to set up a development environment because I want to use different environments, like different versions of Java, different versions of the Antlr tool and runtime, different versions of Node!

Further, this enhancement re-introduces the version skew problem, a central requirement for Antlr4BuildTasks: Never download the Antlr4 Tool .jar because you will select the wrong tool with the wrong runtime.

This option breaks a central requirement of Antlr4BuildTasks. The tool must be able to select the version of the antlr-ng tool that matches the runtime.