chore: removing trailing whitespace from tutorial/topics .md files

This was done using the following shell command:
```bash
find ./content/tokio/ -name "*.md" | xargs -I {} sed -E -i 's/\s+$//' {}
```

Signed-off-by: AlfredWilmot <[email protected]>

Author: AlfredWilmot

content/tokio/topics/testing.md

@@ -142,7 +142,7 @@ be used as a mock:
 
 ```rust
 # use tokio::io::{AsyncBufReadExt, AsyncRead, AsyncWrite, AsyncWriteExt, BufReader};
-# 
+#
 # async fn handle_connection<Reader, Writer>(
 #     reader: Reader,
 #     mut writer: Writer,

content/tokio/topics/tracing-next-steps.md

@@ -135,7 +135,7 @@ To set up mini-redis, we'll first need to add a few dependencies. Update your
 # Implements the types defined in the Otel spec
 opentelemetry = "0.17.0"
 # Integration between the tracing crate and the opentelemetry crate
-tracing-opentelemetry = "0.17.2" 
+tracing-opentelemetry = "0.17.2"
 # Allows you to export data to Jaeger
 opentelemetry-jaeger = "0.16.0"
 ```

content/tokio/tutorial/async.md

@@ -582,10 +582,10 @@ impl TaskFuture {
     }
 
     fn poll(&mut self, cx: &mut Context<'_>) {
-        // Spurious wake-ups are allowed, even after a future has                                  
-        // returned `Ready`. However, polling a future which has                                   
-        // already returned `Ready` is *not* allowed. For this                                     
-        // reason we need to check that the future is still pending                                
+        // Spurious wake-ups are allowed, even after a future has
+        // returned `Ready`. However, polling a future which has
+        // already returned `Ready` is *not* allowed. For this
+        // reason we need to check that the future is still pending
         // before we call it. Failure to do so can lead to a panic.
         if self.poll.is_pending() {
             self.poll = self.future.as_mut().poll(cx);

content/tokio/tutorial/framing.md

@@ -64,7 +64,7 @@ struct Connection {
 
 impl Connection {
     /// Read a frame from the connection.
-    /// 
+    ///
     /// Returns `None` if EOF is reached
     pub async fn read_frame(&mut self)
         -> Result<Option<Frame>>

content/tokio/tutorial/io.md

@@ -281,7 +281,7 @@ can use [`TcpStream::split`]. The task that processes the echo logic in the serv
 # fn dox(mut socket: TcpStream) {
 tokio::spawn(async move {
     let (mut rd, mut wr) = socket.split();
-    
+
     if io::copy(&mut rd, &mut wr).await.is_err() {
         eprintln!("failed to copy");
     }

content/tokio/tutorial/select.md

@@ -554,15 +554,15 @@ async fn action() {
 
 #[tokio::main]
 async fn main() {
-    let (mut tx, mut rx) = tokio::sync::mpsc::channel(128);    
+    let (mut tx, mut rx) = tokio::sync::mpsc::channel(128);
 #   tokio::spawn(async move {
 #       let _ = tx.send(1).await;
 #       let _ = tx.send(2).await;
 #   });
-    
+
     let operation = action();
     tokio::pin!(operation);
-    
+
     loop {
         tokio::select! {
             _ = &mut operation => break,
@@ -657,17 +657,17 @@ async fn action(input: Option<i32>) -> Option<String> {
 #[tokio::main]
 async fn main() {
     let (mut tx, mut rx) = tokio::sync::mpsc::channel(128);
-    
+
     let mut done = false;
     let operation = action(None);
     tokio::pin!(operation);
-    
+
     tokio::spawn(async move {
         let _ = tx.send(1).await;
         let _ = tx.send(3).await;
         let _ = tx.send(2).await;
     });
-    
+
     loop {
         tokio::select! {
             res = &mut operation, if !done => {

content/tokio/tutorial/shared-state.md

@@ -133,7 +133,7 @@ async fn process(socket: TcpStream, db: Db) {
                 let mut db = db.lock().unwrap();
                 db.insert(cmd.key().to_string(), cmd.value().clone());
                 Frame::Simple("OK".to_string())
-            }           
+            }
             Get(cmd) => {
                 let db = db.lock().unwrap();
                 if let Some(value) = db.get(cmd.key()) {

content/tokio/tutorial/spawning.md

@@ -329,7 +329,7 @@ error: future cannot be sent between threads safely
     |
 6   |     tokio::spawn(async {
     |     ^^^^^^^^^^^^ future created by async block is not `Send`
-    | 
+    |
    ::: [..]spawn.rs:127:21
     |
 127 |         T: Future + Send + 'static,

content/tokio/tutorial/streams.md

@@ -284,7 +284,7 @@ pub trait Stream {
     type Item;
 
     fn poll_next(
-        self: Pin<&mut Self>, 
+        self: Pin<&mut Self>,
         cx: &mut Context<'_>
     ) -> Poll<Option<Self::Item>>;
 
@@ -324,7 +324,7 @@ struct Interval {
 #   type Output = ();
 #   fn poll(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<()> {
 #       Poll::Pending
-#   }  
+#   }
 # }
 
 impl Interval {