s/HugrMut/HugrInternalsMut/ as a sealed trait, and expose a minimal HugrMut (#402)

First step of #284 

Moves the mutating methods to a sealed trait, and makes `HugrMut` `pub`.
It also relates it to `HugrView` via a borrowing method.

Author: aborgna-q

src/builder/build_traits.rs

@@ -31,7 +31,7 @@ use super::{
 
 use crate::Hugr;
 
-use crate::hugr::HugrMut;
+use crate::hugr::HugrInternalsMut;
 
 /// Trait for HUGR container builders.
 /// Containers are nodes that are parents of sibling graphs.

src/builder/cfg.rs

@@ -12,7 +12,7 @@ use crate::types::AbstractSignature;
 
 use crate::Node;
 use crate::{
-    hugr::{HugrMut, NodeType},
+    hugr::{HugrInternalsMut, NodeType},
     type_row,
     types::{ClassicRow, SimpleRow, SimpleType},
     Hugr,

src/builder/conditional.rs

@@ -15,7 +15,7 @@ use super::{
 
 use crate::Node;
 use crate::{
-    hugr::{HugrMut, NodeType},
+    hugr::{HugrInternalsMut, NodeType},
     Hugr,
 };
 

src/builder/dataflow.rs

@@ -11,7 +11,7 @@ use crate::types::{AbstractSignature, Signature};
 
 use crate::resource::ResourceSet;
 use crate::Node;
-use crate::{hugr::HugrMut, Hugr};
+use crate::{hugr::HugrInternalsMut, Hugr};
 
 /// Builder for a [`ops::DFG`] node.
 #[derive(Debug, Clone, PartialEq)]

src/builder/module.rs

@@ -19,7 +19,7 @@ use crate::Node;
 use smol_str::SmolStr;
 
 use crate::{
-    hugr::{HugrMut, NodeType},
+    hugr::{HugrInternalsMut, NodeType},
     Hugr,
 };
 

src/hugr.rs

@@ -10,7 +10,7 @@ pub mod views;
 use std::collections::VecDeque;
 use std::iter;
 
-pub(crate) use self::hugrmut::HugrMut;
+pub(crate) use self::hugrmut::HugrInternalsMut;
 pub use self::validate::ValidationError;
 
 use derive_more::From;