Add Activity feed notifications for work item references in wiki comments

Problem to Solve:

Wiki page comments that reference work items (e.g., Issue X via link) do not generate notifications in the referenced item's Activity feed. This behavior differs from work item-to-work item references, where mentions do appear in the Activity feed. For example, if Issue Y mentions Issue X, it shows up in Issue X's Activity feed, but if a Wiki page comment mentions Issue X, it doesn't.

Why is this important?

1. Enhances Workflow Integration: Better connecting Wiki content with work items strengthens the Wiki's role in the planning and documentation workflow.
2. Improves Discoverability: Team members following specific issues would be notified when relevant Wiki discussions mention their work items, preventing knowledge silos.
3. Maintains Context: Having all references to a work item in its Activity feed, regardless of source, provides a complete picture of where and how that item is being discussed across the platform.

The current gap in Wiki-to-work item reference tracking reduces visibility of potentially valuable Wiki discussions and documentation that could impact work item planning and execution.