Corrected dutch translation

'Map openen' is a bit confusing with either creating a folder or opening one.
Changed string NOT_READABLE_ERR, NOT_FOUND_ERR from 'file' to 'file/directory' in ./src/nls/root/strings.js
adding in placeholder
Merge pull request #9948 from encadyma/fixLockedMessage

Fixed #8410: NOT_READABLE_ERR, NOT_FOUND_ERR in ./src/nls/root/strings.js corrected.
Merge pull request #9804 from ispieter/patch-1

Corrected dutch translation
Merge pull request #9962 from chrispecoraro/patch-6

adding in placeholder
Updated by ALF automation.
Merge pull request #9976 from adobe/alf_localization

ALF Automation