Documentation needed: Toggle functionality for journal abbreviation lists

Description

The PR JabRef/jabref#12912 adds a new feature that allows users to enable/disable journal abbreviation lists. This includes both built-in lists and external CSV files. This functionality needs to be documented in the user guide.

Where to Add

This should be added to the documentation section covering Journal Abbreviations, specifically at: https://docs.jabref.org/advanced/journalabbreviations

Suggested Content

I suggest adding a new subsection titled "Enabling and Disabling Abbreviation Lists" with the following content:

Enabling and Disabling Abbreviation Lists

JabRef allows you to temporarily enable or disable specific journal abbreviation lists without removing them:

• Each abbreviation list (including the built-in list) can be toggled on/off independently
• A checkmark (✓) indicates an enabled list, while a circle (○) indicates a disabled list
• When a list is disabled, journal names found in that list will not be abbreviated or unabbreviated
• Toggle states are saved when you click "Save" and persist between application restarts

To toggle a list:

1. Go to Options → Preferences → Journal Abbreviations
2. Select the abbreviation list you want to toggle
3. Click the toggle button next to the dropdown
4. Click "Save" to store your settings

Related PR

JabRef/jabref#12912

Open the Journal Abbreviations page at docs.jabref.org/advanced/journalabbreviations and review the behavior described in JabRef/jabref#12912. Add the requested “Enabling and Disabling Abbreviation Lists” subsection, including the toggle steps and image, then verify that the rendered documentation accurately explains saving and persistence.