Fix new Rust 1.81 clippy warnings

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/merge_requests/1768>

generic/threadshare/src/runtime/executor/async_wrapper.rs

@@ -541,7 +541,7 @@ unsafe impl<T: IoSafe + Write> IoSafe for std::io::BufWriter<T> {}
 unsafe impl<T: IoSafe + Write> IoSafe for std::io::LineWriter<T> {}
 unsafe impl<T: IoSafe + ?Sized> IoSafe for &mut T {}
 unsafe impl<T: IoSafe + ?Sized> IoSafe for Box<T> {}
-unsafe impl<T: Clone + IoSafe + ?Sized> IoSafe for std::borrow::Cow<'_, T> {}
+unsafe impl<T: Clone + IoSafe> IoSafe for std::borrow::Cow<'_, T> {}
 
 impl<T: Read + Send + 'static> AsyncRead for Async<T> {
     fn poll_read(

generic/threadshare/tests/pipeline.rs

@@ -218,7 +218,7 @@ fn multiple_contexts_proxy() {
             .name(format!("proxysrc-{pipeline_index}").as_str())
             .property(
                 "context",
-                &format!("context-{}", (pipeline_index as u32) % CONTEXT_NB),
+                format!("context-{}", (pipeline_index as u32) % CONTEXT_NB),
             )
             .property("proxy-context", format!("proxy-{pipeline_index}"))
             .build()

net/reqwest/src/reqwesthttpsrc/imp.rs

@@ -74,10 +74,7 @@ impl Default for Settings {
             cookies: Vec::new(),
             iradio_mode: DEFAULT_IRADIO_MODE,
             keep_alive: DEFAULT_KEEP_ALIVE,
-            proxy: match proxy_from_str(std::env::var("http_proxy").ok()) {
-                Ok(a) => a,
-                Err(_) => None,
-            },
+            proxy: proxy_from_str(std::env::var("http_proxy").ok()).unwrap_or_default(),
             proxy_id: None,
             proxy_pw: None,
         }

text/json/src/jsongstenc/imp.rs

@@ -159,10 +159,7 @@ impl JsonGstEnc {
                     let mut state = self.state.lock().unwrap();
                     let caps = e.caps();
                     let s = caps.structure(0).unwrap();
-                    state.format = match s.get::<Option<String>>("format") {
-                        Err(_) => None,
-                        Ok(format) => format,
-                    };
+                    state.format = s.get::<Option<String>>("format").unwrap_or_default();
                 }
 
                 // We send our own caps downstream