Make .gitignore match directories, add fake jsdoc

This is why so many tests were failing as though they couldn't find
test/fixtures/fakeJsdoc. It was never added to the repo, because
.gitignore matched it.

Adding a trailing `/` to `jsdoc/` and other entries resolves this
particular issue.

.gitignore

@@ -1,13 +1,13 @@
 .DS_Store
-.idea
-.vscode
+.idea/
+.vscode/
 TESTS-*.xml
-build
-coverage
-dist
-jsdoc
-node_modules
-out
+build/
+coverage/
+dist/
+jsdoc/
+node_modules/
+out/
 pnpm-debug.log
-tmp
+tmp/
 *.log

test/fixtures/fakeJsdoc/jsdoc

@@ -0,0 +1,69 @@
+#!/usr/bin/env node
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+/**
+ * Fake jsdoc implementation for testing
+ */
+
+import { mkdir, writeFile } from 'node:fs/promises'
+import path from 'node:path'
+import { exit } from 'node:process'
+
+try {
+  const {willGenerate, destination, exitCode} = parseArgs(process.argv.slice(2))
+
+  if (willGenerate && exitCode === 0) {
+    const newSubDir = path.join(destination, 'new-subdir')
+    await mkdir(newSubDir, {recursive: true})
+    await writeFile(path.join(newSubDir, 'index.html'), 'New Hotness')
+  }
+  exit(exitCode)
+
+} catch (err) {
+  console.error(err)
+  exit(1)
+}
+
+/**
+ * The parameters parsed from process.argv by parseArgs()
+ * @typedef {object} ArgsResult
+ * @property {string} destination - the JSDoc destination directory
+ * @property {boolean} willGenerate - true unless -h or --no-input-files present
+ * @property {number} exitCode - the value of --exit-code or 0 by default
+ */
+
+/**
+ * Parses fake jsdoc arguments
+ * @param {string[]} argv - command line arguments
+ * @returns {ArgsResult} - parameters determining fake jsdoc behavior
+ */
+function parseArgs(argv) {
+  let destination = null
+  let willGenerate = true
+  let exitCode = 0
+
+  for (let i = 0; i !== argv.length; ++i) {
+    const arg = argv[i]
+    const nextArg = argv[i+1]
+
+    switch (arg) {
+    case '-d':
+      destination = nextArg
+      break
+
+    case '-h':
+    case '--no-input-files':
+      willGenerate = false
+      break
+
+    case '--exit-code':
+      exitCode = nextArg
+      break
+    }
+  }
+  return {willGenerate, destination, exitCode}
+}