Replace em dashes with hyphens across docs and comments

examples/printer_polymorphism.rs

@@ -4,7 +4,7 @@
 //! - `connect()` is called the same way regardless of vendor (polymorphism),
 //!   but each variant's `impl GenericPrinter` runs completely different
 //!   code (override).
-//! - `dispatch_gcode()` only exists on the two Bambu structs (extension) —
+//! - `dispatch_gcode()` only exists on the two Bambu structs (extension) -
 //!   you have to `match` the enum back down to the concrete type to reach
 //!   it, which is the trade-off for not having implicit downcasting.
 
@@ -35,7 +35,7 @@ async fn main() {
         PrinterHandle::PrusaLink(PrusaLinkPrinter::new("p3", "MK4", "192.168.1.51", "prusa-api-key")),
         PrinterHandle::PrusaSerial(PrusaSerialPrinter::new("p4", "MK3S+", 0)),
         PrinterHandle::Klipper(KlipperPrinter::new("p5", "Voron 2.4", "192.168.1.52")),
-        // No host configured — this one will hit the Err path.
+        // No host configured - this one will hit the Err path.
         PrinterHandle::Klipper(KlipperPrinter::new("p6", "Broken Voron", "")),
     ];
 
@@ -52,7 +52,7 @@ async fn main() {
     // Vendor-only extension: reachable only after matching the concrete
     // variant back out of the enum. BambuV1Printer and BambuV2Printer are
     // separate types now (each *has* a BambuGenericPrinter rather than
-    // being the same struct), so — unlike before the split — this needs
+    // being the same struct), so - unlike before the split - this needs
     // two arms instead of one `A(x) | B(x)` pattern: an or-pattern requires
     // every alternative to bind the same type, and these no longer do.
     for printer in &fleet {
@@ -64,9 +64,9 @@ async fn main() {
     }
 
     // A second trait method, same uniform call site as connect(): every
-    // vendor sends "50%" a completely different way — an MQTT gcode
+    // vendor sends "50%" a completely different way - an MQTT gcode
     // command, Moonraker's native API, gcode over HTTP, gcode over serial
-    // — but the caller doesn't need to know or care which.
+    // - but the caller doesn't need to know or care which.
     println!();
     for printer in &mut fleet {
         let _ = printer.set_fan_speed(50).await;