[SYCL][NFC] Remove __SYCL_INLINE_VER_NAMESPACE macro

[bader]

No description provided.

[bader]

Note for reviewers.
99% of changes are done with "find and replace": __SYCL_INLINE_VER_NAMESPACE(_V1) to inline namespace _V1. clang-format adds a comment // namespace _V1 i.e. inline is dropped in the closing comment.

There are just a few files worth reviewing:

1. sycl/.clang-format
2. sycl/doc/doxygen.cfg.in
3. sycl/include/sycl/detail/defines_elementary.hpp and clang/test/SemaSYCL/Inputs/sycl/detail/defines_elementary.hpp

[sommerlukas]

Only reviewed the following files relating to kernel fusion, those look good.

fusion_properties.hpp
fusion_wrapper.hpp
fusion_wrapper.cpp
fusion_wrapper_impl.cpp
fusion_wrapper_impl.hpp
jit_compiler.cpp
jit_compiler.hpp
jit_device_binaries.cpp
jit_device_binaries.hpp

[PietroGhg]

Native CPU LGTM

[premanandrao]

FE changes look okay to me. (I reviewed just a few random files.)

[steffenlarsen]

LGTM!

[bader]

@intel/llvm-gatekeepers, FYI.
Please, make sure that "ready to merge" patches don't add new uses of __SYCL_INLINE_VER_NAMESPACE macro. The best way to validate is to merge tip of the sycl branch.