message: Fix dead link in contributing.rst
diff: @@ -71,7 +71,7 @@ Areas for Contribution
  * HALs for Backend Targets (OpenCL, Vulkan, SPIR-V, HVX, etc)
  * There is no documentation for the HAL currently. The interface is fairly
  - straightforward and the `OpenCL HAL <tile/hal/opencl>`_ provides a good
  + straightforward and the `OpenCL HAL <../tile/hal/opencl>`_ provides a good
  example of a complete HAL.
  Please follow the process above before embarking on anything major (like
  