doc: Use prompt more often

nixos/doc/manual/configuration/wireless.xml

@@ -37,7 +37,7 @@
   If you are using WPA2 you can generate pskRaw key using
   <command>wpa_passphrase</command>:
 <screen>
-$ wpa_passphrase ESSID PSK
+<prompt>$ </prompt>wpa_passphrase ESSID PSK
 network={
         ssid="echelon"
         #psk="abcdefgh"
@@ -54,10 +54,10 @@ network={
   or you can use it to directly generate the
   <literal>wpa_supplicant.conf</literal>:
 <screen>
-# wpa_passphrase ESSID PSK > /etc/wpa_supplicant.conf</screen>
+<prompt># </prompt>wpa_passphrase ESSID PSK > /etc/wpa_supplicant.conf</screen>
   After you have edited the <literal>wpa_supplicant.conf</literal>, you need to
   restart the wpa_supplicant service.
 <screen>
-# systemctl restart wpa_supplicant.service</screen>
+<prompt># </prompt>systemctl restart wpa_supplicant.service</screen>
  </para>
 </section>