Fix clippy warnings

Author: surban

remoc/src/rch/mpsc/receiver.rs

@@ -293,7 +293,7 @@ impl<T, Codec, const BUFFER: usize, const MAX_ITEM_SIZE: usize> Receiver<T, Code
     /// sending new values.
     #[inline]
     pub fn close(&mut self) {
-        let mut inner = self.inner.as_mut().unwrap();
+        let inner = self.inner.as_mut().unwrap();
         let _ = inner.closed_tx.send(Some(ClosedReason::Closed));
         inner.closed = true;
     }

remoc/src/robs/hash_map.rs

@@ -950,7 +950,7 @@ where
                 };
 
                 let mut inner = inner_task.write().await;
-                let mut inner = match inner.as_mut() {
+                let inner = match inner.as_mut() {
                     Some(inner) => inner,
                     None => return,
                 };

remoc/src/robs/hash_set.rs

@@ -586,7 +586,7 @@ where
                 };
 
                 let mut inner = inner_task.write().await;
-                let mut inner = match inner.as_mut() {
+                let inner = match inner.as_mut() {
                     Some(inner) => inner,
                     None => return,
                 };

remoc/src/robs/vec.rs

@@ -901,7 +901,7 @@ where
                 };
 
                 let mut inner = inner_task.write().await;
-                let mut inner = match inner.as_mut() {
+                let inner = match inner.as_mut() {
                     Some(inner) => inner,
                     None => return,
                 };