Quick adjustments

* Move example description to a module comment
* Remove trait bound

Author: RandomInsano

examples/io_write.rs

@@ -1,8 +1,9 @@
+//! Example showing how one could write to a file or socket instead of a string.
+//! For large metrics registries this will be more memory efficient.
+
 use prometheus_client::{encoding::text::encode, metrics::counter::Counter, registry::Registry};
 use std::io::Write;
 
-/// Example showing how one could write to a file or socket instead of a string.
-/// For large metrics registries this will be more memory efficient
 fn main() {
     let mut registry = <Registry>::with_prefix("stream");
     let request_counter: Counter<u64> = Default::default();
@@ -23,9 +24,7 @@ fn main() {
     assert!(buf.as_bytes() == file);
 }
 
-pub struct IoWriterWrapper<W>(W)
-where
-    W: Write;
+pub struct IoWriterWrapper<W>(W);
 
 impl<W> std::fmt::Write for IoWriterWrapper<W>
 where