HIP: Add language to CMake

Help/command/enable_language.rst

Help/command/project.rst

Help/envvar/HIPCXX.rst

Help/envvar/HIPFLAGS.rst

Help/manual/cmake-env-variables.7.rst

Help/manual/cmake-generator-expressions.7.rst

Help/manual/cmake-properties.7.rst

Help/manual/cmake-variables.7.rst

Help/prop_sf/LANGUAGE.rst

Help/prop_tgt/HIP_ARCHITECTURES.rst

Help/prop_tgt/LANG_COMPILER_LAUNCHER.rst

Help/release/dev/hip.rst

Help/variable/CMAKE_HIP_ARCHITECTURES.rst

Help/variable/CMAKE_LANG_COMPILER_LAUNCHER.rst

Modules/CMakeDetermineCompileFeatures.cmake

Modules/CMakeDetermineHIPCompiler.cmake

Modules/CMakeHIPCompiler.cmake.in

Modules/CMakeHIPCompilerABI.hip

Modules/CMakeHIPCompilerId.hip.in

Modules/CMakeHIPInformation.cmake