feat!: ComposablePass trait allowing sequencing and validation

[acl-cqc]

We have several "passes" atm: monomorphization, dead function removal, constant folding. Each has its own code to allow setting a validation level (before and after that pass).

This PR adds the ability chain (sequence) passes;, and to add validation before+after any pass or sequence; and commons up validation code. The top-level constant_fold_pass (etc.) functions are left as wrappers that do a single pass with validation only in test.

TODO: no actual tests of sequencing yet, heh! Maybe we could combine, hmmm, monomorphization followed by constant folding?

BREAKING CHANGE: quite a lot of calls to current pass routines will break, specific cases include (a) with_validation_level should be done by wrapping a ValidatingPass around the receiver; (b) XXXPass::run() requires use ...ComposablePass (however, such calls will cease to do any validation).

[hugrbot]

This PR contains breaking changes to the public Rust API.

cargo-semver-checks summary

--- failure enum_missing: pub enum removed or renamed ---

Description:
A publicly-visible enum cannot be imported by its prior path. A `pub use` may have been removed, or the enum itself may have been renamed or removed entirely.
      ref: https://doc.rust-lang.org/cargo/reference/semver.html#item-remove
     impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.39.0/src/lints/enum_missing.ron

Failed in:
enum hugr_passes::MonomorphizeError, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-passes/src/monomorphize.rs:282
enum hugr_passes::validation::ValidationLevel, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-passes/src/validation.rs:16
enum hugr_passes::validation::ValidatePassError, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-passes/src/validation.rs:28
enum hugr_passes::const_fold::ConstFoldError, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-passes/src/const_fold.rs:40

--- failure enum_variant_missing: pub enum variant removed or renamed ---

Description:
A publicly-visible enum has at least one variant that is no longer available under its prior name. It may have been renamed or removed entirely.
      ref: https://doc.rust-lang.org/cargo/reference/semver.html#item-remove
     impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.39.0/src/lints/enum_variant_missing.ron

Failed in:
variant RemoveDeadFuncsError::ValidationError, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-passes/src/dead_funcs.rs:31

--- failure inherent_method_missing: pub method removed or renamed ---

Description:
A publicly-visible method or associated fn is no longer available under its prior name. It may have been renamed or removed entirely.
      ref: https://doc.rust-lang.org/cargo/reference/semver.html#item-remove
     impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.39.0/src/lints/inherent_method_missing.ron

Failed in:
ConstantFoldPass::validation_level, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-passes/src/const_fold.rs:48
RemoveDeadFuncsPass::validation_level, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-passes/src/dead_funcs.rs:73
MonomorphizePass::validation_level, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-passes/src/monomorphize.rs:290

--- failure method_requires_different_generic_type_params: method now requires a different number of generic type parameters ---

Description:
A method now requires a different number of generic type parameters than it used to. Uses of this method that supplied the previous number of generic types will be broken.
      ref: https://doc.rust-lang.org/reference/items/generics.html
     impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.39.0/src/lints/method_requires_different_generic_type_params.ron

Failed in:
hugr_passes::const_fold::ConstantFoldPass::run takes 0 generic types instead of 1, in /home/runner/work/hugr/hugr/PR_BRANCH/hugr-passes/src/const_fold.rs:115
hugr_passes::RemoveDeadFuncsPass::run takes 0 generic types instead of 1, in /home/runner/work/hugr/hugr/PR_BRANCH/hugr-passes/src/dead_funcs.rs:87
hugr_passes::MonomorphizePass::run takes 0 generic types instead of 1, in /home/runner/work/hugr/hugr/PR_BRANCH/hugr-passes/src/monomorphize.rs:263

--- failure module_missing: pub module removed or renamed ---

Description:
A publicly-visible module cannot be imported by its prior path. A `pub use` may have been removed, or the module may have been renamed, removed, or made non-public.
      ref: https://doc.rust-lang.org/cargo/reference/semver.html#item-remove
     impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.39.0/src/lints/module_missing.ron

Failed in:
mod hugr_passes::validation, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-passes/src/validation.rs:1

[codecov]

Codecov Report

Attention: Patch coverage is 66.66667% with 50 lines in your changes missing coverage. Please review.

Project coverage is 86.52%. Comparing base (d6b8681) to head (dab7039).

Files with missing lines	Patch %	Lines
hugr-passes/src/composable.rs	33.33%	38 Missing and 6 partials ⚠️
hugr-passes/src/monomorphize.rs	77.77%	1 Missing and 3 partials ⚠️
hugr-passes/src/const_fold.rs	97.67%	1 Missing ⚠️
hugr-passes/src/dead_funcs.rs	95.65%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1895      +/-   ##
==========================================
- Coverage   86.56%   86.52%   -0.04%     
==========================================
  Files         195      195              
  Lines       35724    35736      +12     
  Branches    32537    32549      +12     
==========================================
- Hits        30925    30922       -3     
- Misses       3012     3027      +15     
  Partials     1787     1787              

Flag	Coverage Δ
python	92.34% <ø> (ø)
rust	85.95% <66.66%> (-0.05%)	⬇️

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