doc: posix: mark set and get scope APIs for pthread attr as supported

`pthread_attr_setscope()` and `pthread_attr_getscope()`
are now implemented, mark it so.

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

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

@@ -440,10 +440,10 @@ _POSIX_THREAD_PRIORITY_SCHEDULING
 
     pthread_attr_getinheritsched(),
     pthread_attr_getschedpolicy(),yes
-    pthread_attr_getscope(),
+    pthread_attr_getscope(),yes
     pthread_attr_setinheritsched(),
     pthread_attr_setschedpolicy(),yes
-    pthread_attr_setscope(),
+    pthread_attr_setscope(),yes
     pthread_getschedparam(),yes
     pthread_setschedparam(),yes
     pthread_setschedprio(),yes