feat: move CallGraph into hugr-core

[acl-cqc]

In the short term, this is likely wanted for an upcoming PR on linking.
In the (only-slightly-)longer term, we're likely to want this to include static function type-arguments, where a Call/LoadFunction can refer to multiple functions (e.g. foo<bar>(runtime_args)), which will probably mean adding variants to enum CallGraphEdge. So....

• There is a possibility I could derive #[non_exhaustive] enum CallGraphEdge now, making that (anticipated, hypothetical) future change less breaking. (Probably still breaking, though!)
• This has the cost of making this change breaking now, which it presently is not (because of deprecated re-export in hugr-passes - I think rust-semver checks is wrong here).
• However, rather than re-export, I could duplicate call_graph.rs, with the hugr-core version having non_exhaustive but hugr-passes not.
• I'm not sure this is worth it: static function type-args are likely to be breaking anyway, and the non-exhaustive just delays the point of user-code needing an update until, most likely, it sees a new instance at runtime rather than compile-time....
• Thoughts please?

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.68%. Comparing base (daf6cfe) to head (4660ac4).
⚠️ Report is 16 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2531      +/-   ##
==========================================
+ Coverage   82.66%   82.68%   +0.01%     
==========================================
  Files         252      252              
  Lines       46781    46927     +146     
  Branches    42297    42443     +146     
==========================================
+ Hits        38673    38800     +127     
- Misses       6058     6066       +8     
- Partials     2050     2061      +11     

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python	91.41% <ø> (ø)
rust	81.75% <ø> (+0.01%)	⬆️

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[hugrbot]

This PR contains breaking changes to the public Rust API.
Please deprecate the old API instead (if possible), or mark the PR with a ! to indicate a breaking change.

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/v0.43.0/src/lints/enum_missing.ron

Failed in:
enum hugr_passes::call_graph::CallGraphNode, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-passes/src/call_graph.rs:17
enum hugr_passes::call_graph::CallGraphEdge, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-passes/src/call_graph.rs:9

--- 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/v0.43.0/src/lints/module_missing.ron

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

--- failure struct_missing: pub struct removed or renamed ---

Description:
A publicly-visible struct cannot be imported by its prior path. A `pub use` may have been removed, or the struct 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/v0.43.0/src/lints/struct_missing.ron

Failed in:
struct hugr_passes::call_graph::CallGraph, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-passes/src/call_graph.rs:42

[acl-cqc]

The since here commits me to making a patch release, ho hum....

[lmondada]

This is fine, if 0.22.3 never happens, people will be smart enough to infer this means 0.23 :)

[lmondada]

thanks Alan!

[lmondada]

This is fine, if 0.22.3 never happens, people will be smart enough to infer this means 0.23 :)

[lmondada]

I'm confused - why does semver complain on this change?

EDIT: this is a known issue -> obi1kenobi/cargo-semver-checks#355. We can ignore and override it.

[acl-cqc]

This is following something of a different path in #2555 (I had to include constants!) so I'm gonna close this, and then do it again with hugr-core "StaticGraph" (or some name like that) and add the #[non_exhaustive]s for good measure...