Add hints for enum names

[ucasfl]

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• Improvement

Changelog entry (a user-readable short description of the changes that goes to CHANGELOG.md):

Add hints for Enum names. Closes #17112

[ucasfl]

:) SELECT CAST('Helo' AS Enum('Hello' = 1, 'World' = 2))

SELECT CAST('Helo', 'Enum(\'Hello\' = 1, \'World\' = 2)')

Query id: c963ddd6-1db7-4841-9257-b90fbdbdc5e4


0 rows in set. Elapsed: 0.002 sec. 

Received exception from server (version 21.6.1):
Code: 36. DB::Exception: Received from localhost:9000. DB::Exception: Unknown element 'Helo' for enum, may be you meant: ['Hello']: While processing CAST('Helo', 'Enum(\'Hello\' = 1, \'World\' = 2)').

[alexey-milovidov]

LGTM. Let's also add sh test that will check that hints are present in the exception message.

[alexey-milovidov]

Ok. Also I see that the commit message has strange characters: â�”â�
Could you please push --force with another commit message?

[ucasfl]

Ok. Also I see that the commit message has strange characters: â�”â�
Could you please push --force with another commit message?

Ok.