Typex: improve operation description

src/core/operations/Typex.mjs

@@ -23,7 +23,7 @@ class Typex extends Operation {
 
         this.name = "Typex";
         this.module = "Default";
-        this.description = "Encipher/decipher with the WW2 Typex machine.<br><br>Typex rotors were changed regularly and none are public: a random example set are provided. Later Typexes had a reflector which could be configured with a plugboard: to configure this, enter a string of connected pairs of letters in the reflector box, e.g. <code>AB CD EF</code> connects A to B, C to D, and E to F (you'll need to connect every letter). These Typexes also have an input plugboard: unlike Enigma's plugboard, it's not restricted to pairs, so it's entered like a rotor (without stepping). To create your own rotor, enter the letters that the rotor maps A to Z to, in order, optionally followed by <code>&lt;</code> then a list of stepping points.";
+        this.description = "Encipher/decipher with the WW2 Typex machine.<br><br>Typex was originally built by the British Royal Air Force prior to WW2, and is based on the Enigma machine with some improvements made, including using five rotors with more stepping points and interchangeable wiring cores. It was used across the British and Commonewealth militaries. A number of later variants were produced; here we simulate a WW2 era Mark 22 Typex with plugboards for the reflector and input. Typex rotors were changed regularly and none are public: a random example set are provided.<br><br>To configure the reflector plugboard, enter a string of connected pairs of letters in the reflector box, e.g. <code>AB CD EF</code> connects A to B, C to D, and E to F (you'll need to connect every letter). There is also an input plugboard: unlike Enigma's plugboard, it's not restricted to pairs, so it's entered like a rotor (without stepping). To create your own rotor, enter the letters that the rotor maps A to Z to, in order, optionally followed by <code>&lt;</code> then a list of stepping points.";
         this.infoURL = "https://wikipedia.org/wiki/Typex";
         this.inputType = "string";
         this.outputType = "string";