Clean up code by using Iterator::collect() when constructing instance tables (#2918)

* instances: `Iterator::collect()` instances

* instances: adjust nodes to use iterators

* fix warnings on master

* Bump MSRV

* Port the remaining usages

---------

Co-authored-by: Keavon Chambers <keavon@keavon.com>

node-graph/gcore/src/vector/algorithms/poisson_disk.rs

@@ -182,7 +182,7 @@ where
 	A::Item: Clone,
 	B::Item: Clone,
 {
-	a.flat_map(move |i| (b.clone().map(move |j| (i.clone(), j))))
+	a.flat_map(move |i| b.clone().map(move |j| (i.clone(), j)))
 }
 
 /// A square (represented by its top left corner position and width/height of `square_size`) that is currently a candidate for targetting by the dart throwing process.

node-graph/gcore/src/vector/vector_data.rs

@@ -337,7 +337,7 @@ impl VectorData {
 	/// Returns the number of linear segments connected to the given point.
 	pub fn connected_linear_segments(&self, point_id: PointId) -> usize {
 		self.segment_bezier_iter()
-			.filter(|(_, bez, start, end)| ((*start == point_id || *end == point_id) && matches!(bez.handles, BezierHandles::Linear)))
+			.filter(|(_, bez, start, end)| (*start == point_id || *end == point_id) && matches!(bez.handles, BezierHandles::Linear))
 			.count()
 	}