tweak: Add TwoNumbersToNumber wrapper to function registry.

packages/squiggle-lang/src/rescript/FunctionRegistry/Library/FR_Number.res

@@ -20,6 +20,18 @@ module NumberToNumber = {
     )
 }
 
+module TwoNumbersToNumber = {
+  let make = (name, fn) =>
+    FnDefinition.make(
+      ~name,
+      ~inputs=[FRTypeNumber, FRTypeNumber],
+      ~run=(_, inputs, _, _) => {
+        inputs->Prepare.ToValueTuple.twoNumbers->E.R2.fmap(fn)->E.R2.fmap(Wrappers.evNumber)
+      },
+      (),
+    )
+}
+
 module ArrayNumberDist = {
   let make = (name, fn) => {
     FnDefinition.make(