MDL-63730 lang: Merge English strings from the en_fix language pack

Significant string changes:

* withselectedusers_help, core - removing mention of 'Add a common note'
  as the option no longer exists
* considereddigitalminor and digitalminor_desc, core - more
  child-friendly wording
* configmessagingallusers, core_admin - clearer explanation
* auth_dbtype, auth_db - fixed broken link

lang/en/debug.php

@@ -33,7 +33,7 @@ $string['codingerror'] = 'Coding error detected, it must be fixed by a programme
 $string['configmoodle'] = 'Moodle has not been configured yet. You need to edit config.php first.';
 $string['erroroccur'] = 'An error has occurred during this process';
 $string['invalidarraysize'] = 'Incorrect size of arrays in params of {$a}';
-$string['invalideventdata'] = 'Incorrect eventadata submitted: {$a}';
+$string['invalideventdata'] = 'Incorrect event data submitted: {$a}';
 $string['invalidparameter'] = 'Invalid parameter value detected';
 $string['invalidresponse'] = 'Invalid response value detected';
 $string['missingconfigversion'] = 'Config table does not contain version, can not continue, sorry.';