Docs/admin-guide/mm/damon/usage: update context directory section label

The label for context DAMON sysfs directory section is having name
sysfs_contexts.  The name would be better to be used for the contexts
directory.  Rename it to represent a single context.

Link: https://lkml.kernel.org/r/20231213190338.54146-5-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Documentation/admin-guide/mm/damon/usage.rst

@@ -164,7 +164,7 @@ number (``N``) to the file creates the number of child directories named as
 details).  At the moment, only one context per kdamond is supported, so only
 ``0`` or ``1`` can be written to the file.
 
-.. _sysfs_contexts:
+.. _sysfs_context:
 
 contexts/<N>/
 -------------
@@ -288,7 +288,7 @@ The ``action`` file is for setting and getting the scheme's :ref:`action
 from the file and their meaning are as below.
 
 Note that support of each action depends on the running DAMON operations set
-:ref:`implementation <sysfs_contexts>`.
+:ref:`implementation <sysfs_context>`.
 
  - ``willneed``: Call ``madvise()`` for the region with ``MADV_WILLNEED``.
    Supported by ``vaddr`` and ``fvaddr`` operations set.
@@ -428,7 +428,7 @@ pages of all memory cgroups except ``/having_care_already``.::
     echo N > 1/matching
 
 Note that ``anon`` and ``memcg`` filters are currently supported only when
-``paddr`` :ref:`implementation <sysfs_contexts>` is being used.
+``paddr`` :ref:`implementation <sysfs_context>` is being used.
 
 Also, memory regions that are filtered out by ``addr`` or ``target`` filters
 are not counted as the scheme has tried to those, while regions that filtered