diff --git a/docs/grammar/README.md b/docs/grammar/README.md
index b25a20102e..e7710dd5dc 100644
Binary files a/docs/grammar/README.md and b/docs/grammar/README.md differ
diff --git a/docs/grammar/abnf-grammar.txt b/docs/grammar/abnf-grammar.txt
index e340336d2a..c41b639f79 100644
--- a/docs/grammar/abnf-grammar.txt
+++ b/docs/grammar/abnf-grammar.txt
@@ -369,7 +369,7 @@ input-expression = literal
 
 input-item = identifier ":" input-type "=" input-expression ";"
 
-input-title = "[" identifier "]"
+input-title = "[" ( %s"public" / %s"private" / %s"constant" / %s"const" ) "]"
 
 input-section = input-title *input-item