tree wide: clippy lint fixes

most (not all) where done automatically

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

proxmox-file-restore/src/block_driver.rs

@@ -204,7 +204,6 @@ pub fn complete_block_driver_ids<S: BuildHasher>(
     ALL_DRIVERS
         .iter()
         .map(BlockDriverType::resolve)
-        .map(|d| d.list())
-        .flatten()
+        .flat_map(|d| d.list())
         .collect()
 }