[libc][docs] Add sys/time page to the status of implementations docs (#123000)

These changes ensure that the sys/time header is documented properly
with respect to the issue ( #122006 ) .

Author: StarOne01

libc/docs/CMakeLists.txt

@@ -55,6 +55,7 @@ if (SPHINX_FOUND)
       strings
       sys/mman
       sys/resource
+      sys/time
       sys/wait
       threads
       uchar

libc/docs/headers/index.rst

@@ -28,6 +28,7 @@ Implementation Status
    strings
    sys/mman
    sys/resource
+   sys/time
    sys/wait
    threads
    time

libc/utils/docgen/sys/time.yaml

@@ -0,0 +1,5 @@
+functions:
+  select:
+    in-latest-posix: ''
+  utimes:
+    in-latest-posix: ''