[Doc][Web] Fix build command with DPC++ in documentation webpage (#556)

docs/building_the_project_with_dpcpp.rst

@@ -44,7 +44,7 @@ for Windows`_ for building on Windows):
  mkdir build && cd build
  cmake .. -DCMAKE_CXX_COMPILER=$CXX_COMPILER \ # Should be icpx or clang++
  -DCMAKE_C_COMPILER=$C_COMPILER \ # Should be icx or clang
- -DENABLE_MKLGPU_BACKEND=False \ # Optional: The MKLCPU backend is True by default.
+ -DENABLE_MKLCPU_BACKEND=False \ # Optional: The MKLCPU backend is True by default.
  -DENABLE_MKLGPU_BACKEND=False \ # Optional: The MKLGPU backend is True by default.
  -DENABLE_<BACKEND_NAME>_BACKEND=True \ # Enable any other backend(s) (optional)
  -DENABLE_<BACKEND_NAME_2>_BACKEND=True \ # Multiple backends can be enabled at once.