update error messages and documentation

Author: apparebit

crates/prettytty/src/conn.rs

@@ -176,7 +176,7 @@ impl Connection {
     #[inline]
     pub fn input(&self) -> Input {
         Input {
-            scanner: self.scanner.lock().expect("mutex is not poisoned"),
+            scanner: self.scanner.lock().expect("can't lock poisoned mutex"),
         }
     }
 
@@ -187,7 +187,7 @@ impl Connection {
     #[inline]
     pub fn output(&self) -> Output {
         Output {
-            writer: self.writer.lock().expect("mutex is not poisoned"),
+            writer: self.writer.lock().expect("can't lock poisoned mutex"),
         }
     }
 

crates/prettytty/src/sys/unix.rs

@@ -156,6 +156,9 @@ impl RawConfig {
     }
 
     /// Apply the options to create a new configuration.
+    ///
+    /// If the options do not requires changes to the current configuration,
+    /// this method return `None`.
     pub fn apply(&self, options: &Options) -> Option<Self> {
         let mut state = self.state;