Update comments on graph searches.

lib/src/graph/search.dart

@@ -10,11 +10,20 @@ import 'strategy.dart';
 
 extension SearchGraphExtension<V, E> on Graph<V, E> {
  /// Performs a search for the shortest path between [source] and [target].
+ ///
+ /// - [edgeCost] is a function that returns the cost to traverse an edge
+ /// between two vertices. If no function is provided, the cost is assumed
+ /// to be constant with a weight of _1_.
+ ///
+ /// - [costEstimate] is a function that returns the remaining cost from the
+ /// provided vertex. If an estimate is provided a faster _A*-Search_ is
+ /// performed, otherwise a _Dijkstra Search_.
+ ///
  Path<V>? shortestPath(
  V source,
  V target, {
  num Function(Edge<V, E> edge)? edgeCost,
- num Function(V target)? costEstimate,
+ num Function(V vertex)? costEstimate,
  StorageStrategy<V>? vertexStrategy,
  }) =>
  shortestPathAll(
@@ -25,11 +34,20 @@ extension SearchGraphExtension<V, E> on Graph<V, E> {
  vertexStrategy: vertexStrategy,
  ).firstOrNull;
 
- /// Performs a search for the shortest paths between [source] and [target],
- /// where the target is specified as a predicate over the vertices.
+ /// Performs a search for the shortest paths between [source] and the
+ /// [targetPredicate] predicate.
+ ///
+ /// - [edgeCost] is a function that returns the cost to traverse an edge
+ /// between two vertices. If no function is provided, the cost is assumed
+ /// to be constant with a weight of _1_.
+ ///
+ /// - [costEstimate] is a function that returns the remaining cost from the
+ /// provided vertex. If an estimate is provided a faster _A*-Search_ is
+ /// performed, otherwise a _Dijkstra Search_.
+ ///
  Iterable<Path<V>> shortestPathAll(
  V source,
- Predicate1<V> target, {
+ Predicate1<V> targetPredicate, {
  num Function(Edge<V, E> edge)? edgeCost,
  num Function(V target)? costEstimate,
  StorageStrategy<V>? vertexStrategy,
@@ -42,14 +60,14 @@ extension SearchGraphExtension<V, E> on Graph<V, E> {
  return costEstimate == null
  ? DijkstraSearchIterable<V>(
  startVertices: [source],
- targetPredicate: target,
+ targetPredicate: targetPredicate,
  successorsOf: successorsOf,
  edgeCost: vertexEdgeCost,
  vertexStrategy: vertexStrategy,
  )
  : AStarSearchIterable<V>(
  startVertices: [source],
- targetPredicate: target,
+ targetPredicate: targetPredicate,
  successorsOf: successorsOf,
  costEstimate: costEstimate,
  edgeCost: vertexEdgeCost,