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/tape/test/alloc_writable_media.rs

@@ -173,7 +173,7 @@ fn test_alloc_writable_media_4() -> Result<(), Error> {
     // next call fail because there is no free media
     assert!(pool.alloc_writable_media(start_time + 5).is_err());
 
-    // Create new nedia set, so that previous set can expire
+    // Create new media set, so that previous set can expire
     pool.start_write_session(start_time + 10)?;
 
     assert!(pool.alloc_writable_media(start_time + 10).is_err());