Move hardcoded error strings in RemoveRegisterAttribute and GenerateCompressedAssembliesNativeSourceFiles to Properties.Resources

[Copilot]

Two MSBuild tasks used Log.LogError with hardcoded, non-localized strings and no XA error codes. This replaces them with Log.LogCodedError using Properties.Resources entries.

Changes

• New error codes XA2024 / XA2025 added to Resources.resx and Resources.Designer.cs
• RemoveRegisterAttribute.cs and GenerateCompressedAssembliesNativeSourceFiles.cs — replaced Log.LogError with Log.LogCodedError
• Documentation — added xa2024.md, xa2025.md, and updated index.md

// Before
Log.LogError ($"Unable to load assembly '{mono_android}'");
Log.LogError ($"Assembly {assembly.ItemSpec} does not exist");

// After
Log.LogCodedError ("XA2024", Properties.Resources.XA2024, mono_android);
Log.LogCodedError ("XA2025", Properties.Resources.XA2025, assembly.ItemSpec);

[Copilot]

Pull request overview

This PR localizes previously hardcoded MSBuild task error strings by introducing new XA error codes and moving the message text into Properties.Resources, aligning these tasks with the rest of Xamarin.Android.Build.Tasks error-reporting patterns.

Changes:

• Added new localized resource strings and error codes XA2024 / XA2025.
• Updated RemoveRegisterAttribute and GenerateCompressedAssembliesNativeSourceFiles tasks to use Log.LogCodedError with Properties.Resources.
• Added documentation pages for XA2024 / XA2025 and linked them from the messages index.

Reviewed changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/Xamarin.Android.Build.Tasks/Tasks/RemoveRegisterAttribute.cs	Switches assembly-load failure logging to Log.LogCodedError with XA2024.
src/Xamarin.Android.Build.Tasks/Tasks/GenerateCompressedAssembliesNativeSourceFiles.cs	Switches missing-assembly logging to Log.LogCodedError with XA2025.
src/Xamarin.Android.Build.Tasks/Properties/Resources.resx	Adds localized strings for XA2024 and XA2025.
src/Xamarin.Android.Build.Tasks/Properties/Resources.Designer.cs	Adds strongly-typed accessors for XA2024 / XA2025.
Documentation/docs-mobile/messages/xa2024.md	Adds documentation for XA2024.
Documentation/docs-mobile/messages/xa2025.md	Adds documentation for XA2025.
Documentation/docs-mobile/messages/index.md	Adds links/entries for XA2024 and XA2025.

Files not reviewed (1)

• src/Xamarin.Android.Build.Tasks/Properties/Resources.Designer.cs: Language not supported