improve doc

Co-authored-by: vaaaaanquish <47341845+vaaaaanquish@users.noreply.github.com>

Author: paq

README.md

@@ -17,7 +17,7 @@ brew install cmake libomp
 On Windows
 
 1. Install CMake and VS Build Tools.
-1. Install LLVM and set an environment variable `LIBCLANG_PATH` to `C:\Program Files\LLVM\bin`
+1. Install LLVM and set an environment variable `LIBCLANG_PATH` to PATH_TO_LLVM_BINARY (example: `C:\Program Files\LLVM\bin`)
 
 Please see below for details.