Reliably set environment variables on Windows and Mac

[soypat]

Windows

During quick install of windows tinygo using the tinygo release (not scoop) the instructions suggest setting PATH environment variable with set https://tinygo.org/getting-started/install/windows/

This does not set the PATH permanently, so tinygo will only work during that shell session. Best way to go about setting PATH permanently on windows is via the "Environment Variables"system config dialog box.

Mac

Same for mac, export just sets the environment in current shell.

To set PATH on every shell one can edit their shell profile. This depends on what shell they use.

echo $SHELL

For zsh users, this is .zshrc. For bash users this is .bashrc. Find the file in your home folder and add export PATH=$PATH:/path/to/your/tinygo to the end:

nano $HOME/.zshrc
# or for bash users:
nano $HOME/.bashrc

[aykevl]

Can you make a PR to update the docs here?
https://github.com/tinygo-org/tinygo-site/blob/release/content/getting-started/install/windows.md