[doc] Fix the link to block disablein useless-import-alias related

Author: Pierre-Sassoulas

doc/data/messages/u/useless-import-alias/related.rst

@@ -1,3 +1,3 @@
 - `PEP 8, Import Guideline <https://peps.python.org/pep-0008/#imports>`_
-- `Pylint block-disable <https://pylint.pycqa.org/en/latest/user_guide/message-control.html#block-disables>`_
+- `Pylint block-disable <block_disables>`_
 - `mypy --no-implicit-reexport <https://mypy.readthedocs.io/en/stable/command_line.html#cmdoption-mypy-no-implicit-reexport>`_

doc/user_guide/messages/message_control.rst

@@ -23,6 +23,7 @@ In order to control messages, ``pylint`` accepts the following values:
 
 * All the checks with ``all``
 
+.. _block_disables:
 
 Block disables
 --------------