Fix clippy "warning: called Iterator::last on a DoubleEndedIterator" lint

Fixing this because (quoting the clippy warning) "this will needlessly
iterate the entire iterator".

Author: simu

src/lib.rs

@@ -170,7 +170,7 @@ fn walk_entity_dir(
                     // only base name for all nodes regardless of depth if compose-node-name isn't
                     // enabled.
                     (
-                        cls.split(MAIN_SEPARATOR).last().ok_or(anyhow!(
+                        cls.split(MAIN_SEPARATOR).next_back().ok_or(anyhow!(
                             "Can't shorten node name for {}",
                             entry.path().display()
                         ))?,

src/node/nodeinfo.rs

@@ -73,7 +73,7 @@ impl NodeInfoMeta {
             vec![self
                 .parts
                 .iter()
-                .last()
+                .next_back()
                 .ok_or(anyhow!("Unable to extract last segment from node"))?
                 .to_str()
                 .ok_or(anyhow!("Unable to convert path segment to a string"))?]