Fix doc for storage

[open-junius]

Description

The pr improves the doc for storage definition in subtensor pallet.

Related Issue(s)

• Closes Incorrect placement of Rustdoc comments on storage variables #2099

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Other (please describe):

Breaking Change

If this PR introduces a breaking change, please provide a detailed description of the impact and the migration path for existing applications.

Checklist

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have run cargo fmt and cargo clippy to ensure my code is formatted and linted correctly
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

Screenshots (if applicable)

Please include any relevant screenshots or GIFs that demonstrate the changes made.

Additional Notes

Please provide any additional information or context that may be helpful for reviewers.

[l0r1s]

This file needs a cleanup because this makes no sense to wrap the #[pallet::constant] into a type value, we can just use it like that, type_value derives a Get<T> implementation that is already existing for InitialDefaultDelegateTake

Also, a lot of these type values are not used anywhere

edit: I added this to the #2047 issue

[open-junius]

I assigned the #2047 to me. Let's merge the PR at first, then we have correct doc for rust doc and type script. I will create a new PR for 2047.

[sam0x17]

merge conflict @juniuszhou