Create combined diagnostic page for property syntax

[BillWagner]

Fixes #49593

Create a single page for all errors and warnings related to properties.

Pull in the section on field-based properties from the partial types diagnostic page.

While in these files, perform a general edit pass.

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Internal previews

📄 File	🔗 Preview link
.github/prompts/error-consolidation.md	Copilot prompts to consolidate error codes.
docs/csharp/language-reference/compiler-messages/partial-declarations.md	Errors and warnings related to partial type and partial member declarations
docs/csharp/language-reference/compiler-messages/property-declaration-errors.md	Compiler Errors on property declarations
docs/csharp/language-reference/toc.yml	docs/csharp/language-reference/toc
docs/csharp/misc/sorry-we-don-t-have-specifics-on-this-csharp-error.md	Sorry, we don't have specifics on this C# error

[Copilot]

Pull request overview

This PR consolidates property-related compiler errors and warnings into a single comprehensive diagnostic page, improving documentation discoverability and maintainability by bringing together scattered error documentation from individual files and the misc folder.

Key changes:

• Creates a new consolidated page property-declaration-errors.md covering 41 error codes related to property declarations, including readonly properties, auto-implemented properties, field-backed properties, required members, ref-returning properties, and property initializers
• Removes field-backed property documentation from partial-declarations.md (CS9258, CS9263, CS9264, CS9266, CS9273) since these errors are more closely related to property declarations than partial declarations
• Updates TOC and redirection mappings to ensure all deleted error pages redirect to the new consolidated page

Reviewed changes

Copilot reviewed 16 out of 16 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
docs/csharp/language-reference/compiler-messages/property-declaration-errors.md	New consolidated documentation covering 41 property-related compiler errors and warnings with detailed explanations and resolution steps
docs/csharp/language-reference/compiler-messages/partial-declarations.md	Removes field-backed property section (moved to property-declaration-errors.md) and updates error code lists
docs/csharp/language-reference/toc.yml	Adds new property declarations entry with displayName listing all covered error codes and moves field-backed property codes from partial declarations section
docs/csharp/misc/sorry-we-don-t-have-specifics-on-this-csharp-error.md	Removes 22 error codes that now have proper documentation in the consolidated page
.openpublishing.redirection.csharp.json	Adds redirects for 8 deleted individual error pages (cs0200.md, cs0545.md, cs0571.md, cs0840.md, cs1014.md, cs1043.md, cs8145.md, cs9036.md)
docs/csharp/misc/cs0200.md, cs1014.md, cs1043.md	Deleted individual error pages now consolidated into property-declaration-errors.md
docs/csharp/language-reference/compiler-messages/cs0545.md, cs0571.md, cs0840.md, cs8145.md, cs9036.md	Deleted individual error pages now consolidated into property-declaration-errors.md
docs/csharp/language-reference/compiler-messages/snippets/partial-declarations/	Removed unused snippet files (CS0759Examples.cs and project file) as the examples were replaced with consolidated guidance
.github/prompts/error-consolidation.md	Updated prompt configuration to target property declaration errors