UPDATE: Adds minimal generated documented functions (#22)

See #21

xlsx/src/bin/documentation.rs

@@ -0,0 +1,17 @@
+//! Produces documentation of all the implemented IronCalc functions
+//! and saves the result to functions.md
+//!
+//! Usage: documentation
+
+use std::fs;
+
+use ironcalc_base::model::Model;
+
+fn main() {
+    let mut doc = Vec::new();
+    for function in Model::documentation() {
+        doc.push(function.name);
+    }
+    let data = doc.join("\n");
+    fs::write("functions.md", data).expect("Unable to write file");
+}