[name] Fix doc

That's part of an enum now.
diff --git a/docs/harfbuzz-sections.txt b/docs/harfbuzz-sections.txt
index 6280817..6e2aab4 100644
--- a/docs/harfbuzz-sections.txt
+++ b/docs/harfbuzz-sections.txt
@@ -599,7 +599,6 @@
 hb_ot_name_get_utf16
 hb_ot_name_get_utf32
 hb_ot_name_get_utf8
-HB_OT_NAME_ID_INVALID
 hb_ot_name_id_t
 hb_ot_name_entry_t
 </SECTION>