Improve the SQL tab-completion feature for resource group

[fairyfar]

What does this PR do?

Improve the SQL tab-completion feature for resource group

When manually typing the SQL for resource group management in the psql client, the auto-completion(tab-completion) function is not complete enough.
In particular, the auto-completion of the ALTER RESOURCE GROUP command is lacking.

For example, auto-completion cannot continue after "ALTER RESOURCE ".

Key points of modification:

1. For the time being, we will not handle the tab-completion feature of resource queue because there is a trend for resource group to replace resource queue.
2. Correct the description of the gp_resource_manager parameter.

Type of Change

• Bug fix (non-breaking change)
• New feature (non-breaking change)
• Breaking change (fix or feature with breaking changes)
• Documentation update

Breaking Changes

Test Plan

• Unit tests added/updated
• Integration tests added/updated
• Passed make installcheck
• Passed make -C src/test installcheck-cbdb-parallel

Impact

Performance:

User-facing changes:

Dependencies:

Checklist

• Followed contribution guide
• Added/updated documentation
• Reviewed code for security implications
• Requested review from cloudberry committers

Additional Context

CI Skip Instructions

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[my-ship-it]

LGTM
Clean, focused fix that addresses a real usability gap.
Only suggestion: confirm group-v2 is already a supported gp_resource_manager value.

[leborchuk]

Yes, here https://github.com/apache/cloudberry/blob/main/src/backend/cdb/cdbvars.c#L526 we check if gp_resource_manager could one of 3 supported items, not 2 as was in previous help string

Also here the set of resource group grama and options https://github.com/apache/cloudberry/blob/main/src/backend/parser/gram.y#L1752 - SQL syntax was correctly reflected in a tab completion and options are the same as in a gram.y

LGTM

[fairyfar]

LGTM Clean, focused fix that addresses a real usability gap. Only suggestion: confirm group-v2 is already a supported gp_resource_manager value.

Sorry to reply you later.
Yes, group-v2 is supported.
Now, "group-v2" parameter value was used in CI test job "ic-resgroup-v2".