[FRAME] Warn on unchecked weight witness

[ggwpez]

Adds a warning to FRAME pallets when a function argument that starts with _ is used in the weight formula.
This is in most cases an error since the weight witness needs to be checked.

Example:

#[pallet::call_index(0)]
#[pallet::weight(T::SystemWeightInfo::remark(_remark.len() as u32))]
pub fn remark(_origin: OriginFor<T>, _remark: Vec<u8>) -> DispatchResultWithPostInfo {
	Ok(().into())
}

Produces this warning:

warning: use of deprecated constant `pallet::warnings::UncheckedWeightWitness_0::_w`: 
                 It is deprecated to not check weight witness data.
                 Please instead ensure that all witness data for weight calculation is checked before usage.
         
                 For more info see:
                     <https://github.com/paritytech/polkadot-sdk/pull/1818>
   --> substrate/frame/system/src/lib.rs:424:40
    |
424 |         pub fn remark(_origin: OriginFor<T>, _remark: Vec<u8>) -> DispatchResultWithPostInfo {
    |                                              ^^^^^^^
    |
    = note: `#[warn(deprecated)]` on by default

Can be suppressed like this, since in this case it is legit:

#[pallet::call_index(0)]
#[pallet::weight(T::SystemWeightInfo::remark(remark.len() as u32))]
pub fn remark(_origin: OriginFor<T>, remark: Vec<u8>) -> DispatchResultWithPostInfo {
	let _ = remark; // We dont need to check the weight witness.
	Ok(().into())
}

Changes:

• Add warning on uncheded weight witness
• Respect subkeys limit in System::kill_prefix
• Fix HRMP pallet and other warnings
• Updateproc_macro_warning dependency
• Delete random folder substrate/src/src 🙈
• Adding Prdoc

[liamaharon]

was deleting this file intentional?

[ggwpez]

As far as i can tell it was a duplicate of substrate/src/lib.rs. Dont think we need this 🤔

[joepetrowski]

Looks good except my question about clearing defunct voters.

[bkchr]

This is still the default schema?

[ggwpez]

Yes, i used the prdoc schema and prdoc check.