Issue #3216430 by Charlie ChX Negyesi: Improve documentation on $is_syncing

(cherry picked from commit 20c8eef1)

core/lib/Drupal/Core/Extension/module.api.php

@@ -183,7 +183,9 @@ function hook_module_preinstall($module) {
  *   TRUE if the module is being installed as part of a configuration import. In
  *   these cases, your hook implementation needs to carefully consider what
  *   changes, if any, it should make. For example, it should not make any
- *   changes to configuration objects or entities.
+ *   changes to configuration objects or configuration entities. Those changes
+ *   should be made earlier and exported so during import there's no need to
+ *   do them again.
  *
  * @see \Drupal\Core\Extension\ModuleInstaller::install()
  * @see hook_install()
@@ -230,8 +232,9 @@ function hook_modules_installed($modules, $is_syncing) {
  * @param bool $is_syncing
  *   TRUE if the module is being installed as part of a configuration import. In
  *   these cases, your hook implementation needs to carefully consider what
- *   changes, if any, it should make. For example, it should not make any
- *   changes to configuration objects or entities.
+ *   changes to configuration objects or configuration entities. Those changes
+ *   should be made earlier and exported so during import there's no need to
+ *   do them again.
  *
  * @see \Drupal\Core\Config\ConfigInstallerInterface::isSyncing
  * @see hook_schema()
@@ -269,8 +272,9 @@ function hook_module_preuninstall($module) {
  * @param bool $is_syncing
  *   TRUE if the module is being uninstalled as part of a configuration import.
  *   In these cases, your hook implementation needs to carefully consider what
- *   changes, if any, it should make. For example, it should not make any
- *   changes to configuration objects or entities.
+ *   changes to configuration objects or configuration entities. Those changes
+ *   should be made earlier and exported so during import there's no need to
+ *   do them again.
  *
  * @see hook_uninstall()
  */
@@ -307,8 +311,9 @@ function hook_modules_uninstalled($modules, $is_syncing) {
  * @param bool $is_syncing
  *   TRUE if the module is being uninstalled as part of a configuration import.
  *   In these cases, your hook implementation needs to carefully consider what
- *   changes, if any, it should make. For example, it should not make any
- *   changes to configuration objects or entities.
+ *   changes to configuration objects or configuration entities. Those changes
+ *   should be made earlier and exported so during import there's no need to
+ *   do them again.
  *
  * @see hook_install()
  * @see hook_schema()