Documentation typo: wrong page flag bit for KPF_HUGE

The correct value 17 can be found later in this document
and in the kernel-page-flags.h header (KPF_HUGE). I noticed
this while implementing vmprobe's kpageflags support.
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

Documentation/vm/pagemap.txt

@@ -62,7 +62,7 @@ There are four components to pagemap:
     14. SWAPBACKED
     15. COMPOUND_HEAD
     16. COMPOUND_TAIL
-    16. HUGE
+    17. HUGE
     18. UNEVICTABLE
     19. HWPOISON
     20. NOPAGE