* make types within `generate_solution_type` macro explicit
Closes#8444.
Just changes the parsing logic for that macro; does not change any
emitted code. The associated types associated with the macro now
require explicit, keyword-style declaration.
**Old**:
```rust
sp_npos_elections::generate_solution_type!(
#[compact]
pub struct TestCompact::<VoterIndex, TargetIndex, PerU16>(16)
);
```
**New**:
```rust
sp_npos_elections::generate_solution_type!(
#[compact]
pub struct TestCompact::<VoterIndex = VoterIndex, CandidateIndex = TargetIndex, Accuracy = PerU16>(16)
);
```
* un-ignore doc-tests
* use new form in bin/node/runtime/
* rename CandidateIndex -> TargetIndex
* add tests demonstrating some potential compile failures
* Fix incorrect use of syn::exports
Instead of using `syn::exports` we should import the trait from the
quote crate directly.
* Use own macro for test cases to fix compilation with latest syn
* Fix test
* Bump version
* update test-utils crates to be ready for publishing
* adding changelog
* Adding automaticly generated READMEs
* fixing versions
* another version mishap
Bastian Köcher