This is a port (and hopefully a small improvement) of @Kianenigma

's PR
from the old Substrate repo:
https://github.com/paritytech/substrate/pull/13987. Following #1689 I
moved the documentation of all macros relevant to this PR from
`frame_support_procedural` to `pallet_macros` while including a hint for
RA users.

Question: Again with respect to #1689: Is there a good reason why we
should *not* enhance paths with links to our current rustdocs? For
example, instead of
```rust
/// **Rust-Analyzer users**: See the documentation of the Rust item in
/// `frame_support::pallet_macros::storage`.
```
we could write
```rust
/// **Rust-Analyzer users**: See the documentation of the Rust item in
/// [`frame_support::pallet_macros::storage`](https://paritytech.github.io/polkadot-sdk/master/frame_support/pallet_macros/attr.storage.html).
```
This results in a clickable link like this:
<img width="674" alt="image"
src="https://github.com/paritytech/polkadot-sdk/assets/10713977/c129e622-3942-4eeb-8acf-93ee4efdc99d">
I don't really expect the links to become outdated any time soon, but I
think this would be a great UX improvement over just having paths.

TODOs:
- [ ] Add documentation for `constant_name` macro
- [x] Add proper documentation for different `QueryKinds`, i.e.
`OptionQuery`, `ValueQuery`, `ResultQuery`. One example for each. Custom
`OnEmpty` should be moved to `QueryKinds` trait doc page.
- [ ] Rework `type_value` docs

---------

Co-authored-by: kianenigma <[email protected]>