docs(tutorial/Tutorial): add to PATH in Windows

[bladefistx2]

user may need to add the directory to the PATH variable.

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[bladefistx2]

Signed.

[googlebot]

CLAs look good, thanks!

[gkalpak]

@bladefistx2, the Node installer takes care of that automatically. Did you run into this issue yourself ?

In any case, I think it is outside of the scope of the Angular tutorial to provide troubleshooting instructions for Node.js installation.

_{BTW, I noticed that the download link mentioned a couple of lines above seems to have changed.
The url should be https://nodejs.org/en/download/. Feel free to submit a PR for that 😃}

[gkalpak]

Closed with c2033d7.