Explain 'Case sensitive file system' option for SMB/CIFS external storage

[hweihwang]

It appears the "Case sensitive file system" option for SMB/CIFS external storage mounts isn't currently covered in the Nextcloud admin manual (https://docs.nextcloud.com/server/latest/admin_manual/configuration_files/external_storage/smb.html). This might lead to some user uncertainty about its precise behavior and how to best configure it.

Adding a section to the SMB documentation about this could be quite helpful. Here's a summary of how this option is understood to function, which might be useful for the documentation:

• Core Function: The main idea is that this option helps Nextcloud understand whether the SMB server's file system is case-sensitive or not. It doesn't make Nextcloud itself enforce a specific case behavior on the storage.
• When the option is ON (checked):
  • Nextcloud generally treats filenames with different capitalizations as separate files (e.g., "File.txt" is different from "file.txt").
  • File existence checks are typically done with exact case matching.
• When the option is OFF (unchecked):
  • This signals to Nextcloud that the SMB share doesn't distinguish by case.
  • Nextcloud might then use case-insensitive methods for comparisons or when scanning directories for files.