Add graphviz output to puffin-dev resolve-cli (#443)

I added output in graphviz DOT format to `puffin-dev resolve-cli` to
help with debugging resolutions. This requires tracking the requested
ranges in the graph. I also fixed the direction of the graph.

 Output for `black`:

```dot
digraph {
    0 [ label="click\n8.1.7"]
    1 [ label="black\n23.11.0"]
    2 [ label="packaging\n23.2"]
    3 [ label="mypy-extensions\n1.0.0"]
    4 [ label="tomli\n2.0.1"]
    5 [ label="pathspec\n0.11.2"]
    6 [ label="typing-extensions\n4.8.0"]
    7 [ label="platformdirs\n4.0.0"]
    1 -> 0 [ label=">=8.0.0"]
    1 -> 3 [ label=">=0.4.3"]
    1 -> 5 [ label=">=0.9.0"]
    1 -> 4 [ label=">=1.1.0"]
    1 -> 6 [ label=">=4.0.1"]
    1 -> 2 [ label=">=22.0"]
    1 -> 7 [ label=">=2"]
}
```


![image](4a440fcd-6248-4349-8e1a-c3e0363e42b1)

transformers:


![image](a13a693c-a8c0-4a4f-95d9-3458431c678a)

jupyter:


![graphviz](ef730033-6fd9-4ea9-ac93-8c874c19a101)

crates/puffin-resolver/src/resolution.rs

@@ -3,6 +3,7 @@ use std::hash::BuildHasherDefault;
 use colored::Colorize;
 use fxhash::FxHashMap;
 use petgraph::visit::EdgeRef;
+use petgraph::Direction;
 use pubgrub::range::Range;
 use pubgrub::solver::{Kind, State};
 use pubgrub::type_aliases::SelectedDependencies;
@@ -51,7 +52,7 @@ impl Resolution {
 /// A complete resolution graph in which every node represents a pinned package and every edge
 /// represents a dependency between two pinned packages.
 #[derive(Debug)]
-pub struct Graph(petgraph::graph::Graph<Dist, (), petgraph::Directed>);
+pub struct Graph(petgraph::graph::Graph<Dist, Range<PubGrubVersion>, petgraph::Directed>);
 
 impl Graph {
     /// Create a new graph from the resolved `PubGrub` state.
@@ -98,8 +99,12 @@ impl Graph {
         // Add every edge to the graph.
         for (package, version) in selection {
             for id in &state.incompatibilities[package] {
-                if let Kind::FromDependencyOf(self_package, self_version, dependency_package, _) =
-                    &state.incompatibility_store[*id].kind
+                if let Kind::FromDependencyOf(
+                    self_package,
+                    self_version,
+                    dependency_package,
+                    dependency_range,
+                ) = &state.incompatibility_store[*id].kind
                 {
                     let PubGrubPackage::Package(self_package, None, _) = self_package else {
                         continue;
@@ -112,7 +117,7 @@ impl Graph {
                     if self_version.contains(version) {
                         let self_index = &inverse[self_package];
                         let dependency_index = &inverse[dependency_package];
-                        graph.update_edge(*dependency_index, *self_index, ());
+                        graph.update_edge(*self_index, *dependency_index, dependency_range.clone());
                     }
                 }
             }
@@ -179,6 +184,13 @@ impl Graph {
             })
             .collect()
     }
+
+    /// Return the underlying graph.
+    pub fn petgraph(
+        &self,
+    ) -> &petgraph::graph::Graph<Dist, Range<PubGrubVersion>, petgraph::Directed> {
+        &self.0
+    }
 }
 
 /// Write the graph in the `{name}=={version}` format of requirements.txt that pip uses.
@@ -198,8 +210,8 @@ impl std::fmt::Display for Graph {
 
             let mut edges = self
                 .0
-                .edges(index)
-                .map(|edge| &self.0[edge.target()])
+                .edges_directed(index, Direction::Incoming)
+                .map(|edge| &self.0[edge.source()])
                 .collect::<Vec<_>>();
             edges.sort_unstable_by_key(|package| package.name());