Use '$' as shell prompt in README.md

Replaced the ❯ prompt symbol with the conventional $ prompt in the
README’s example output for `ip a`, improving consistency and
readability.

Author: otischung

README.md

@@ -53,7 +53,7 @@ To exit kvm-host, press "Ctrl-A", release both keys, and then press "x".
 1. Start the kvm-host emulator. Once initialized, the TUN/TAP interface (for example, `tap0`) is visible in the output of `ip a`. The following is sample output from the host:
 
    ```shell
-   ❯ ip a
+   $ ip a
    1: lo: ...
    2: eth0: ...
    3: wlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
@@ -69,7 +69,7 @@ To exit kvm-host, press "Ctrl-A", release both keys, and then press "x".
 2. Execute the shell script `./scripts/set-host-bridge.sh`, which configures a bridge by assigning the default route to 10.0.0.1, integrating the TUN/TAP interface into the bridge, and activating the network interfaces. The following is sample output of `ip a` from the host:
 
    ```shell
-   ❯ ip a
+   $ ip a
    ...
    11: tap0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
        link/ether 5a:1d:bd:2d:7c:1f brd ff:ff:ff:ff:ff:ff