query.ebnf: fix PRIMARY KEY definition

doc/sql/query.ebnf

@@ -144,7 +144,7 @@ create_role    ::= 'CREATE' 'ROLE' role
 create_table   ::= 'CREATE' 'TABLE' table
                    '('
                        column type ('NOT'? 'NULL')? ('PRIMARY' 'KEY')? (',' column type ('NOT'? 'NULL')? ('PRIMARY' 'KEY')?)*
-                       (',' 'PRIMARY KEY' '(' column (',' column)* ')')?
+                       (',' 'PRIMARY' 'KEY' '(' column (',' column)* ')')?
                    ')'
                    ('USING' ('MEMTX' | 'VINYL'))?
                    ('DISTRIBUTED' (('BY' '(' column (',' column)*  ')' ('ON' 'TIER' '(' tier ')')?) | 'GLOBALLY'))