Documentation(864191): Fixed the issues in the Blazor Mention Working with Data UG

[kathiravan4982]

Description

Documentation(864191): Fixed the following issues in the Blazor Mention "Working with Data" UG documentation:

• Fixed the CS1503 compilation error in the OnActionComplete sample by using the generic ActionCompleteEventArgs<TItem> signature that matches SfMention<TItem>.OnActionComplete.
• Removed the stray s character after the <style> tag in action-begin.razor that would have broken all CSS.
• Standardized the event handler naming to OnActionBeginHandler for casing consistency across all event code samples.
• Added API reference links for ActionBeginEventArgs, ActionCompleteEventArgs<TItem>, MentionChar, PopupWidth, SuggestionCount, and Offline.
• Clarified the OnActionFailure handler parameter type as System.Exception and linked it to the MSDN reference.
• Added an N> note in the ExpandoObject section explaining why @using System.Dynamic; is required.
• Added an N> note in the OData v4 section cautioning that the public Northwind endpoint can be retired or rate-limited.
• Added an N> note about CORS configuration when using CrossDomain="true" on SfDataManager for remote data.
• Expanded the Offline mode description to specify the dataset is cached in-memory on initialization and subsequent filtering happens client-side.
• Standardized @code{ to @code { (with space) across the four working-with-data code samples that used the no-space form.
• Added an intro paragraph that calls out the Events section.
• Renamed the MentionChar sample field to CurrencyChar in primitive-type-int.razor for clearer readability.
• Made component-level data fields private (where the markup binding permits) for proper encapsulation in the code samples.

Code Studio usage(Mandatory)

• Code Studio used in this PR/MR?

  • Yes
  • No

• If Yes: Primary use (choose one)

  • Generate new content
  • Refactor/improve existing content
  • Review assistance (explanations/summaries)
  • Other:

• Outcome

  • Saved time
  • Neutral
  • Cost time

• If “Cost time” explain in short (1 or 2 lines):

Type of Change

• New documentation page
• Update to existing documentation
• Bug fix (broken links, typos, formatting issues)
• Structural change (folders, navigation, index)
• Content improvement (clarity, examples, screenshots)
• Other (please describe):

Reviewer Checklist (Mandatory)

• Reviewed the provided Code Studio usages related information
• Content changes follow UG/Documentation guidelines
• All provided information reviewed and verified
• Links and previews checked

[SyncfusionBuild]

Build Status: INPROGRESS 🔃
Build Location: 864191-MentionUG

[SyncfusionBuild]

CI Status: SUCCESS ✅
Source Compilation: SUCCESS ✅
Build Location: 864191-MentionUG
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
MD File Encoding 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: 864191-MentionUG

[SyncfusionBuild]

CI Status: SUCCESS ✅
Source Compilation: SUCCESS ✅
Build Location: 864191-MentionUG
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
MD File Encoding 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