doc: posix: mark ftruncate as supported

Add POSIX FD_MGMT option and mark ftruncate as supported
in POSIX Option group Documentation

Signed-off-by: Karthikeyan Krishnasamy <karthikeyan@linumiz.com>

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

@@ -78,7 +78,7 @@ Realtime Controller System Profile (PSE52)
     POSIX_C_LANG_MATH, yes, :ref:`POSIX_C_LANG_MATH <posix_option_group_c_lang_math>`
     POSIX_C_LANG_SUPPORT, yes, :ref:`POSIX_C_LANG_SUPPORT <posix_option_group_c_lang_support>`
     POSIX_DEVICE_IO,, :ref:`†<posix_undefined_behaviour>`
-    POSIX_FD_MGMT,,
+    POSIX_FD_MGMT,, :ref:`POSIX_FD_MGMT <posix_option_group_fd_mgmt>`
     POSIX_FILE_LOCKING,,
     POSIX_FILE_SYSTEM,,
     POSIX_SIGNALS,, :ref:`†<posix_undefined_behaviour>`
@@ -135,7 +135,7 @@ Dedicated Realtime System Profile (PSE53)
     POSIX_C_LANG_MATH, yes, :ref:`POSIX_C_LANG_MATH <posix_option_group_c_lang_math>`
     POSIX_C_LANG_SUPPORT, yes, :ref:`POSIX_C_LANG_SUPPORT <posix_option_group_c_lang_support>`
     POSIX_DEVICE_IO,, :ref:`†<posix_undefined_behaviour>`
-    POSIX_FD_MGMT,,
+    POSIX_FD_MGMT,, :ref:`POSIX_FD_MGMT <posix_option_group_fd_mgmt>`
     POSIX_FILE_LOCKING,,
     POSIX_FILE_SYSTEM,,
     POSIX_MULTI_PROCESS,, :ref:`†<posix_undefined_behaviour>`

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

@@ -406,6 +406,30 @@ POSIX_TIMERS
     timer_getoverrun(),yes
     timer_settime(),yes
 
+.. _posix_option_group_fd_mgmt:
+
+POSIX_FD_MGMT
+=============
+
+This table lists service support status in Zephyr for `POSIX_FD_MGMT`:
+
+.. csv-table:: POSIX_FD_MGMT
+   :header: API, Supported
+   :widths: 50,10
+
+    dup(),
+    dup2(),
+    fcntl(),
+    fgetpos(),
+    fseek(),
+    fseeko(),
+    fsetpos(),
+    ftell(),
+    ftello(),
+    ftruncate(),yes
+    lseek(),
+    rewind(),
+
 .. _posix_options:
 
 Additional POSIX Options