Installer for windows sets path/environment variable wrongly on Windows 11.

1. First of all the installer defaults to "no", do not automatically add, which is weird for a default setting.

2. Second, I set it to yet add it automatically and it did it wrong (in windows 11 environment settings):

It added this line of text to "PATH" variable which is WRONG:

set LIBCLANG_PATH=G:\Tools\LLVM\bin

it add:

G:\Tools\LLVM\bin

3. It also fails to set an additional environment variable properly in windows 11 environment settings:

LIBCLANG_PATH=G:\Tools\LLVM\bin

This should be fixed it will help people who don't check these kinds of things and they might be baffled why it's not working on windows 11...

(At least I think this is what happened, there is a 0.01% chance I did this myself, but I don't think so... I was busy with other settings though, but I am pretty sure the installer did it wrong, it's kinda rare to see installers do this kind of thing wrong, you know...)

Start by reproducing the installer behavior on Windows 11 with the environment-variable option enabled, then inspect the installer’s handling of PATH and LIBCLANG_PATH. Done means the default setting is appropriate and both variables are written as separate, valid Windows environment settings without the set command being inserted into PATH.

Written by the indexing model from the issue text.