[BUG] Cannot create a grant select on specific columns with salt.states.mysql_grants.present

Description
SQL (and by extension, mysql) admits that a grant select may apply a subset of columns of a given table.

The concrete syntax is
GRANT SELECT (abc, def) ON test.table_test TO test_user@127.0.0.1

salt.states.mysql_grants.present does not appear to be able to generate this statement.

Setup
Beforehand (assuming mysql is set up), create an SQL table somewhere:

create table table_test (
  abc int not null primary key,
  def int,
  secret int
);

Now create the appropriate configuration in an .sls file.

test_user:
  mysql_user.present:
    - host: 127.0.0.1
    - password_hash: '*DEADBEEF'
test_user_grant:
  mysql_grants.present:
    - grant: SELECT (abc, def)
    - database: test.table_test
    - user: test_user
    - host: 127.0.0.1

Attempting to highstate results in:

 Failed to execute: "GRANT SELECT (abc, def) ON test.table_test TO test_user@127.0.0.1"

• on-premises
• bare-metal Ubuntu 18.04
• not sure about packaging/install

Steps to Reproduce the behavior

state.highstate results in an error. The relevant debug clearly shows howthings get mangled when the query is tokenised:

[DEBUG   ] _grant_to_tokens entry 'GRANT SELECT (`abc`, `def`) ON `test`.`table_test` TO `test_user`@`127.0.0.1`'
[DEBUG   ] grant to token '`test_user`'::'`127.0.0.1`'::'['SELECT', 'SELECT.`abc`', 'SELECT.`def`']'::'`test`.`table_test`'

Expected behavior

[DEBUG   ] _grant_to_tokens entry 'GRANT SELECT (`abc`, `def`) ON `test`.`table_test` TO `test_user`@`127.0.0.1`'
[DEBUG   ] grant to token '`test_user`'::'`127.0.0.1`'::'['SELECT(`abc`, `def`)']'::'`test`.`table_test`'

(and the restricted column grant is applied)

Versions Report

Start by locating the _grant_to_tokens entry point mentioned in the debug output and reproduce the issue with the provided .sls configuration and MySQL table. Compare the current tokenization with the expected single SELECT(abc, def) token, then verify with state.highstate that the restricted column grant is applied.