Misleading Default Placeholder (pdf) in "Extension Override Setting" Causes Configuration Errors

[DehanLUO]

Dear @trganda,

First and foremost, I would like to express my sincere appreciation for your work on this plugin. It has significantly improved my workflow in Obsidian by streamlining attachment management, saving me both time and effort.

I am writing to kindly request a small adjustment to the default placeholder text in the Extension Override Setting sub-panel.

Whenever I click on Add extension overrides, a placeholder suggesting pdf appears in the input field. While I now understand that the intention may be to guide users to enter a valid file extension to enable the feature correctly, the current placeholder may unintentionally mislead users, myself included, into thinking that pdf is either the default or preconfigured value.

This confusion persisted until I noticed that the feature was not functioning as expected. Upon further inspection of the .obsidian/plugins/attachment-management/data.json file, I discovered that the "extension" field remained empty in the relevant configuration entry. This clarified that I was in fact required to enter a specific file extension pdf manually.

A brief GIF here to illustrate the process and better contextualize the issue. In practice, I do configure pdf in more detail later on.

To enhance clarity and prevent potential user misunderstanding, I suggest revising the placeholder text to something more descriptive, such as:

Please enter a file extension (e.g., pdf)

Thank you once again for developing and maintaining this excellent plugin. I truly appreciate your consideration.

Best regards,
Dehan