typo fixes all over the place

found and semi-manually replaced by using:
 codespell -L mut -L crate -i 3 -w

Mostly in comments, but also email notification and two occurrences
of misspelled  'reserved' struct member, which where not used and
cargo build did not complain about the change, soo ...

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

src/client/backup_writer.rs

@@ -509,7 +509,7 @@ impl BackupWriter {
     }
 
     // We have no `self` here for `h2` and `verbose`, the only other arg "common" with 1 other
-    // funciton in the same path is `wid`, so those 3 could be in a struct, but there's no real use
+    // function in the same path is `wid`, so those 3 could be in a struct, but there's no real use
     // since this is a private method.
     #[allow(clippy::too_many_arguments)]
     fn upload_chunk_info_stream(

src/client/vsock_client.rs

@@ -86,7 +86,7 @@ impl tower_service::Service<Uri> for VsockConnector {
 
             Ok(connection)
         })
-        // unravel the thread JoinHandle to a useable future
+        // unravel the thread JoinHandle to a usable future
         .map(|res| match res {
             Ok(res) => res,
             Err(err) => Err(format_err!("thread join error on vsock connect: {}", err)),