concat: cs & php &py

[ttodua]

in addition to concat,
example files were not being resolved correctly with relative path and I couldnt make them work otherwise
(i.e. if you use this launch.json debugger config:

{
        "name": "c# example",
        "type": "node",
        "request": "launch",
        "runtimeExecutable": "npx",
        "runtimeArgs": [
            "tsx"
        ],
        "args": ["${workspaceFolder}\\examples\\cs\\interop-non-transpilable-code\\transpiler.ts"],
        "skipFiles": ["<node_internals>/**", "node_modules/**"],
      }