Support enterpriseServerVersions in Liquid statements (#16058)

* remove outdated and redundant context.enterpriseVersions and add new context.enterpriseServerVersions

* update references from context.enterpriseVersions -> context.enterpriseServerReleases

* add test

* also test oldest supported enterprise version in addition to the latest

* Script to update not-free-pro-team conditionals (#16060)

* script to update not-free-pro-team conditionals

* change string to regex so we can do replace all

* remove stray test.only

* Update middleware/context.js

Co-authored-by: James M. Greene <JamesMGreene@github.com>

* Update tests/unit/page.js

Co-authored-by: James M. Greene <JamesMGreene@github.com>

* Update tests/unit/page.js

Co-authored-by: James M. Greene <JamesMGreene@github.com>

* Update tests/fixtures/page-versioned-for-all-enterprise-releases.md

Co-authored-by: James M. Greene <JamesMGreene@github.com>

Co-authored-by: James M. Greene <JamesMGreene@github.com>

tests/unit/page.js

@@ -1,6 +1,7 @@
 const path = require('path')
 const cheerio = require('cheerio')
 const Page = require('../../lib/page')
+const allVersionIds = Object.keys(require('../../lib/all-versions'))
 const enterpriseServerReleases = require('../../lib/enterprise-server-releases')
 const nonEnterpriseDefaultVersion = require('../../lib/non-enterprise-default-version')
 // get the `free-pro-team` segment of `free-pro-team@latest`
@@ -121,6 +122,43 @@ describe('Page class', () => {
       const $ = cheerio.load(rendered)
       expect($('a[href="/capistrano"]').length).toBe(1)
     })
+
+    // Most of our Liquid versioning tests are in https://github.com/docs/render-content,
+    // But they don't have access to our currently supported versions, which we're testing here.
+    // This test ensures that this works as expected: {% if enterpriseServerVersions contains currentVersion %}
+    test('renders the expected Enterprise Server versioned content', async () => {
+      const page = new Page({
+        relativePath: 'page-versioned-for-all-enterprise-releases.md',
+        basePath: path.join(__dirname, '../fixtures'),
+        languageCode: 'en'
+      })
+      // set version to the latest enteprise version
+      const context = {
+        currentVersion: `enterprise-server@${enterpriseServerReleases.latest}`,
+        currentLanguage: 'en',
+        enterpriseServerVersions: allVersionIds.filter(id => id.startsWith('enterprise-server@'))
+      }
+      let rendered = await page.render(context)
+      let $ = cheerio.load(rendered)
+      expect($.text()).toBe('This text should render on any actively supported version of Enterprise Server')
+      expect($.text()).not.toBe('This text should only render on non-Enterprise')
+
+      // change version to the oldest enterprise version, re-render, and test again;
+      // the results should be the same
+      context.currentVersion = `enterprise-server@${enterpriseServerReleases.oldestSupported}`
+      rendered = await page.render(context)
+      $ = cheerio.load(rendered)
+      expect($.text()).toBe('This text should render on any actively supported version of Enterprise Server')
+      expect($.text()).not.toBe('This text should only render on non-Enterprise')
+
+      // change version to non-enterprise, re-render, and test again;
+      // the results should be the opposite
+      context.currentVersion = nonEnterpriseDefaultVersion
+      rendered = await page.render(context)
+      $ = cheerio.load(rendered)
+      expect($.text()).not.toBe('This text should render on any actively supported version of Enterprise Server')
+      expect($.text()).toBe('This text should only render on non-Enterprise')
+    })
   })
 
   test('preserves `languageCode`', () => {