SHOW CREATE QUOTA treats CURRENT as a name rather than a different clause

[MyroTk]

Describe the bug
SHOW CREATE QUOTA CURRENT does not show show create for the current quota, but rather sees CURRENT as the name of the quota and produces an exception.

How to reproduce
ClickHouse server version 20.6.1 revision 54436.
SHOW CREATE QUOTA CURRENT
SHOW CREATE QUOTA

Expected behavior
Both SHOW CREATE QUOTA CURRENT and SHOW CREATE QUOTA should return the same result.

Error message and/or stacktrace

ClickHouse client version 20.6.1.4066 (official build).
Connecting to localhost:9000 as user default.
Connected to ClickHouse server version 20.6.1 revision 54436.

clicktest :) SHOW CREATE QUOTA CURRENT

SHOW CREATE QUOTA CURRENT


Received exception from server (version 20.6.1):
Code: 199. DB::Exception: Received from localhost:9000. DB::Exception: There is no quota `CURRENT` in [disk, users.xml].

0 rows in set. Elapsed: 0.008 sec.

clicktest :) SHOW CREATE QUOTA

SHOW CREATE QUOTA

┌─CREATE QUOTA─────────────────────────────────────────────────────────────────────────┐
│ CREATE QUOTA default KEYED BY user_name FOR INTERVAL 1 hour TRACKING ONLY TO default │
└──────────────────────────────────────────────────────────────────────────────────────┘

1 rows in set. Elapsed: 0.005 sec.

clicktest :)