Add support of referential constraints directly in column defininions:

create table t1 (id1 int primary key);
create table t2 (id2 int references t1(id1));

Referenced field name can be omitted if equal to foreign field name:

create table t1 (id int primary key);
create table t2 (id int references t1);

Until 10.5 this syntax was understood by the parser but was silently
ignored.

In case of generated columns this syntax is disabled at parser level
by ER_PARSE_ERROR. Note that separate FOREIGN KEY clause for generated
columns is disabled at storage engine level.