add export alert.js

Author: Srabutdotcom

src/mod.ts

@@ -1,4 +1,5 @@
 export * from "./enum.js";
 export * from "./extensiontype.js"
 export * from "./handshaketype.js"
-export * from "./signaturescheme.js"
+export * from "./signaturescheme.js"
+export * from "./alert.js"