1013906: Add an "Events" section documenting feature-specific Spreadsheet events.

[DinakarManickam4212]

UG-1013906: Add a dedicated "Events" section to the Spreadsheet documentation. For each feature, list and describe the events it triggers, including the event name, when it fires, event parameters, and a short code example demonstrating usage.

[SyncfusionBuild]

Build Status: INPROGRESS 🔃
Build Location: EJ2-1013906-dev

[SyncfusionBuild]

CI Status: SUCCESS ✅
Source Compilation: SUCCESS ✅
Build Location: EJ2-1013906-dev
Technical Error(s): 0
Spelling Error(s): 0
Image Alt Text Error(s): 0
Image Size Error(s): 0
Image Name Error(s): 0
Front matter Error(s): 0
File Path Error(s): 0
CodeSnippet File Path Missing Error(s): 0
Toc Anchor Tags Validation Error(s): 0
MD Tag Validation Error(s): 0

[SyncfusionBuild]

Build Status: INPROGRESS 🔃
Build Location: EJ2-1013906-dev

[SyncfusionBuild]

CI Status: SUCCESS ✅
Source Compilation: SUCCESS ✅
Build Location: EJ2-1013906-dev
Technical Error(s): 0
Spelling Error(s): 0
Image Alt Text Error(s): 0
Image Size Error(s): 0
Image Name Error(s): 0
Front matter Error(s): 0
File Path Error(s): 0
CodeSnippet File Path Missing Error(s): 0
Toc Anchor Tags Validation Error(s): 0
MD Tag Validation Error(s): 0