docs: fix memory.low description in cgroup-v2.rst

The current cgroup-v2.rst file contains an incorrect description of when
memory is reclaimed from a cgroup that is using the 'memory.low'
mechanism. This fix simply corrects the text to reflect the actual
implementation.

Fixes: 7854207f ("mm/docs: describe memory.low refinements")
Signed-off-by: NJon Haslam <jonhaslam@fb.com>
Acked-by: NRoman Gushchin <guro@fb.com>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

Documentation/admin-guide/cgroup-v2.rst

@@ -1117,8 +1117,8 @@ PAGE_SIZE multiple when read back.
 
 	Best-effort memory protection.  If the memory usage of a
 	cgroup is within its effective low boundary, the cgroup's
-	memory won't be reclaimed unless memory can be reclaimed
-	from unprotected cgroups.
+	memory won't be reclaimed unless there is no reclaimable
+	memory available in unprotected cgroups.
 
 	Effective low boundary is limited by memory.low values of
 	all ancestor cgroups. If there is memory.low overcommitment
@@ -1914,7 +1914,7 @@ Cpuset Interface Files
 
         It accepts only the following input values when written to.
 
-        "root"   - a paritition root
+        "root"   - a partition root
         "member" - a non-root member of a partition
 
 	When set to be a partition root, the current cgroup is the