do full sync when Antora reverts to running a full build (#12263)

lib/antora/extensions/autoconfig-partial-build.js

@@ -1,7 +1,8 @@
 'use strict'
 
 const execFile = require('node:util').promisify(require('node:child_process').execFile)
-const { promises: fsp } = require('node:fs')
+const fsp = require('node:fs/promises')
+const ospath = require('node:path')
 
 module.exports.register = function () {
   if (!process.env.BUILD_REFNAME) return
@@ -26,7 +27,8 @@ module.exports.register = function () {
     const versionsInManifest = siteManifestData.components.ROOT.versions
     if (!(version in versionsInManifest && isBranch === !!versionsInManifest[version].prerelease)) {
       const category = require('path').basename(module.id, '.js')
-      this.getLogger(category).info(`version ${version} not previously built; reverting to full build`)
+      await fsp.writeFile(ospath.join(playbook.dir, '.full-build'), '')
+      console.log(`version ${version} not previously built; reverting to full build`)
       return
     }
     Object.assign(