docs: add file header

Also:
- test: clarify test

tests/lib/espree.js

@@ -1,9 +1,22 @@
+/**
+ * @fileoverview Tests for EspreeParser.
+ * @author Brett Zamir
+ */
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
 import assert from "assert";
 import * as acorn from "acorn";
 import espree from "../../lib/espree.js";
 
+//------------------------------------------------------------------------------
+// Tests
+//------------------------------------------------------------------------------
+
 describe("espree", () => {
-    it("Throws upon `jsx_readString` when not using JSX", () => {
+    it("Throws upon `jsx_readString` call when not using JSX", () => {
         const espreeParserFactory = espree();
         const AcornParser = acorn.Parser;
         const EspreeParser = espreeParserFactory(/** @type {EspreeParser} */ (AcornParser));

tools/js-for-ts.js

@@ -1,5 +1,20 @@
+/**
+ * @fileoverview Tool to prepare JavaScript (+JSDoc) for TypeScript, inlining
+ * `@local`-marked `@typedef`'s, and building a faux class for `@export`-marked
+ * classes so the type can be exported out of a given file.
+ * @author Brett Zamir
+ */
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
 import js2tsAssistant from "@es-joy/js2ts-assistant";
 
+// ----------------------------------------------------------------------------
+// Modify output
+// ----------------------------------------------------------------------------
+
 await js2tsAssistant({
     customClassHandling({
         ast, builders, superClassName