doc: posix: options: correct anchor for thread safe functions

Previously, the anchor for `_POSIX_THREAD_SAFE_FUNCTIONS` was
`posix_thread_safe_functions` but it should have been
`posix_option_thread_safe_functions`.

Signed-off-by: Chris Friedt <[email protected]>

Author: cfriedt

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

@@ -44,7 +44,7 @@ POSIX System Interfaces
     :ref:`_POSIX_REALTIME_SIGNALS<posix_option_group_realtime_signals>`, -1, :kconfig:option:`CONFIG_POSIX_REALTIME_SIGNALS`
     :ref:`_POSIX_SEMAPHORES<posix_option_group_semaphores>`, 200809L, :kconfig:option:`CONFIG_POSIX_SEMAPHORES`
     :ref:`_POSIX_SPIN_LOCKS<posix_option_group_spin_locks>`, 200809L, :kconfig:option:`CONFIG_POSIX_SPIN_LOCKS`
-    :ref:`_POSIX_THREAD_SAFE_FUNCTIONS<posix_thread_safe_functions>`, -1, :kconfig:option:`CONFIG_POSIX_THREAD_SAFE_FUNCTIONS`
+    :ref:`_POSIX_THREAD_SAFE_FUNCTIONS<posix_option_thread_safe_functions>`, -1, :kconfig:option:`CONFIG_POSIX_THREAD_SAFE_FUNCTIONS`
     :ref:`_POSIX_THREADS<posix_option_group_threads_base>`, -1, :kconfig:option:`CONFIG_POSIX_THREADS`
     :ref:`_POSIX_TIMEOUTS<posix_option_timeouts>`, 200809L, :kconfig:option:`CONFIG_POSIX_TIMEOUTS`
     :ref:`_POSIX_TIMERS<posix_option_group_timers>`, 200809L, :kconfig:option:`CONFIG_POSIX_TIMERS`

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

@@ -979,7 +979,7 @@ Enable this option with :kconfig:option:`CONFIG_POSIX_THREAD_PRIORITY_SCHEDULING
     pthread_setschedparam(),yes
     pthread_setschedprio(),yes
 
-.. _posix_thread_safe_functions:
+.. _posix_option_thread_safe_functions:
 
 _POSIX_THREAD_SAFE_FUNCTIONS
 ++++++++++++++++++++++++++++