Fix docs reference (#1017)

Author: blink1073

docs/kernels.rst

@@ -192,7 +192,7 @@ Packaging
 =========
 
 To release your kernel as a Python package, we recommend following the pattern
-used in the :ref:`echo_kernel`, which uses the `hatch`_  build backend and
+used in the `echo_kernel`_, which uses the `hatch`_  build backend and
 a build file that creates the kernel directory with the ``kernel.json`` and
 kernel icons, which is included as ``shared-data``, ending up in the
 ``share/jupyter/kernels/`` folder in the user's installed environment.
@@ -201,3 +201,4 @@ See `pyproject.toml`_ and `hatch_build.py`_ for more details.
 .. _hatch: https://hatch.pypa.io/latest/
 .. _pyproject.toml: https://github.com/jupyter/echo_kernel/blob/main/pyproject.toml
 .. _hatch_build.py: https://github.com/jupyter/echo_kernel/blob/main/hatch_build.py
+.. _echo_kernel: https://github.com/jupyter/echo_kernel