doc: posix: mark sched_setparam & sched_setscheduler as supported

`sched_setparam()` and `sched_setscheduler()` is now implemented,
mark it so.

signed-off-by: Gaetan Perrot <gaetanperrotpro@gmail.com>

doc/services/portability/posix/option_groups/index.rst

@@ -380,8 +380,8 @@ _POSIX_PRIORITY_SCHEDULING
     sched_getparam(),
     sched_getscheduler(),
     sched_rr_get_interval(),
-    sched_setparam(),
-    sched_setscheduler(),
+    sched_setparam(),yes
+    sched_setscheduler(),yes
     sched_yield(),yes
 
 .. _posix_option_reader_writer_locks: