Fix Commands button to show correct shortcut on Windows and Linux (#3625)

* Fix Commands button to show correct shortcut

* Fix onboarding to use the same shortcut reference

* Rename test file to be more general

* Add test for commands button text

* Remove outdated reference to Ctrl+/

* Change shortcut separator to be + and no spaces

* Add JSDocs and improve comments

* Add unit tests

* Change control modifier to regular ASCII caret

* Add browser test and fix platform detection

* A snapshot a day keeps the bugs away! 📷🐛 (OS: ubuntu-latest)

* Add useful debug info to the error message

* Fix to display metaKey as Super on Linux

* Revert "A snapshot a day keeps the bugs away! 📷🐛 (OS: windows-latest)"

This reverts commit f8da90d5d2.

* A snapshot a day keeps the bugs away! 📷🐛 (OS: windows-latest)

* Approve snapshots

---------

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: Jess Frazelle <jessfraz@users.noreply.github.com>

e2e/playwright/app-header-tests.spec.ts

@@ -0,0 +1,66 @@
+import { test, expect } from '@playwright/test'
+
+import { setupElectron, tearDown } from './test-utils'
+
+test.afterEach(async ({ page }, testInfo) => {
+  await tearDown(page, testInfo)
+})
+
+test.describe('Electron app header tests', () => {
+  test(
+    'Open Command Palette button has correct shortcut',
+    { tag: '@electron' },
+    async ({ browserName }, testInfo) => {
+      const { electronApp, page } = await setupElectron({
+        testInfo,
+        folderSetupFn: async () => {},
+      })
+
+      await page.setViewportSize({ width: 1200, height: 500 })
+
+      // No space before the shortcut since it checks textContent.
+      let text
+      switch (process.platform) {
+        case 'darwin':
+          text = 'Commands⌘K'
+          break
+        case 'win32':
+          text = 'CommandsCtrl+K'
+          break
+        default: // 'linux' etc.
+          text = 'CommandsCtrl+K'
+          break
+      }
+      const commandsButton = page.getByRole('button', { name: 'Commands' })
+      await expect(commandsButton).toBeVisible()
+      await expect(commandsButton).toHaveText(text)
+
+      await electronApp.close()
+    }
+  )
+
+  test(
+    'User settings has correct shortcut',
+    { tag: '@electron' },
+    async ({ browserName }, testInfo) => {
+      const { electronApp, page } = await setupElectron({
+        testInfo,
+        folderSetupFn: async () => {},
+      })
+
+      await page.setViewportSize({ width: 1200, height: 500 })
+
+      // Open the user sidebar menu.
+      await page.getByTestId('user-sidebar-toggle').click()
+
+      // No space after "User settings" since it's textContent.
+      const text =
+        process.platform === 'darwin' ? 'User settings⌘,' : 'User settingsCtrl,'
+      const userSettingsButton = page.getByTestId('user-settings')
+      await expect(userSettingsButton).toBeVisible()
+      await expect(userSettingsButton).toHaveText(text)
+
+      await electronApp.close()
+    }
+  )
+})