Merge rust-bitcoin/rust-bitcoin#2791: Removed spare line at end of headers in units crate

101378c4d0 Removed //! spare line at end of headers (jamil.lambert)

Pull request description:

  Some of the headers had a //! at the end but most didn't. They have all been removed in units/src/ to make the files consistent

ACKs for top commit:
  apoelstra:
    ACK 101378c4d0

Tree-SHA512: 7f6e343ae48e3a5fe82f24c3b9cfe843b9c52458e164cd77e4d3cd3e455bc6636986305270b970b909c59bd241bc379f68912bb9a4b79b07b0638c193c1c8109

units/src/amount.rs

@@ -1745,7 +1745,7 @@ pub mod serde {
     pub mod as_sat {
         //! Serialize and deserialize [`Amount`](crate::Amount) as real numbers denominated in satoshi.
         //! Use with `#[serde(with = "amount::serde::as_sat")]`.
-        //!
+
         use serde::{Deserializer, Serializer};
 
         use super::private;