docs: posix: fix for unimplemented functions

The following functions are not implemented:
- getc_unlocked()
- getchar_unlocked()
- putc_unlocked()
- putchar_unlocked()

Signed-off-by: Yong Cong Sin <[email protected]>

Author: ycsin

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

@@ -900,16 +900,16 @@ _POSIX_THREAD_SAFE_FUNCTIONS
     flockfile(),
     ftrylockfile(),
     funlockfile(),
-    getc_unlocked(), yes
-    getchar_unlocked(), yes
+    getc_unlocked(),
+    getchar_unlocked(),
     getgrgid_r(),
     getgrnam_r(),
     getpwnam_r(),
     getpwuid_r(),
     gmtime_r(), yes
     localtime_r(),
-    putc_unlocked(), yes
-    putchar_unlocked(), yes
+    putc_unlocked(),
+    putchar_unlocked(),
     rand_r(), yes
     readdir_r(),
     strerror_r(), yes