Move hardcoded error strings in JCWGenerator.cs to Properties.Resources with XA error codes

[Copilot]

Four LogError calls in JCWGenerator.cs used hardcoded interpolated strings instead of localized resource strings with XA#### codes. This replaces them with LogCodedError using new resource entries.

New error codes

• XA4253 — Generated JCW code changed unexpectedly (line 110)
• XA4217 — Architecture has Java types missing from template architecture (lines 191-196, consolidated from per-type loop into single message)
• XA4227 — Marshal method mismatch across architectures (line 271)

Changes

• Properties/Resources.resx / Resources.Designer.cs — Added XA4253, XA4217, XA4227 resource strings
• Utilities/JCWGenerator.cs — Replaced LogError → LogCodedError at all four call sites; collapsed the type-list loop into a single sorted, string.Join'd message
• Documentation/docs-mobile/messages/ — Added xa4253.md, xa4217.md, xa4227.md; updated index.md

// Before
logger.LogError ($"Architecture '{state.TargetArch}' has Java types which have no counterparts in template architecture '{templateState.TargetArch}':");
foreach (var type in typesSet)
    logger.LogError ($"  {type}");

// After
typesSet.ExceptWith (templateSet);
var typesList = string.Join (", ", typesSet.OrderBy (t => t, StringComparer.Ordinal));
logger.LogCodedError ("XA4217", Properties.Resources.XA4217, state.TargetArch, templateState.TargetArch, typesList);

Note: XA4253 was chosen instead of XA4212 because XA4212 is already used in XAJavaTypeScanner.cs for the IJavaObject without Java.Lang.Object error. XA4217 is also used in external/Java.Interop for a Kotlin method override error (different resource key JavaCallableWrappers_XA4217). The index lists both uses.

[Copilot]

Pull request overview

This PR updates JCWGenerator error reporting to use localized Properties.Resources strings and LogCodedError calls with XA error codes, and adds corresponding documentation pages for the new/updated messages.

Changes:

• Replaced hardcoded LogError strings in Utilities/JCWGenerator.cs with LogCodedError and new resource entries (XA4212/XA4217/XA4227).
• Added new XA resource strings to Properties/Resources.resx (and updated Resources.Designer.cs).
• Added message documentation pages (xa4212.md, xa4217.md, xa4227.md) and updated Documentation/docs-mobile/messages/index.md.

Reviewed changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
src/Xamarin.Android.Build.Tasks/Utilities/JCWGenerator.cs	Switches several error logs to LogCodedError and consolidates one multi-line error into a single message.
src/Xamarin.Android.Build.Tasks/Properties/Resources.resx	Adds new XA resource strings used by JCWGenerator.
src/Xamarin.Android.Build.Tasks/Properties/Resources.Designer.cs	Regenerates resource accessors for the new XA entries.
Documentation/docs-mobile/messages/xa4212.md	Adds docs page for XA4212.
Documentation/docs-mobile/messages/xa4217.md	Adds docs page for XA4217.
Documentation/docs-mobile/messages/xa4227.md	Adds docs page for XA4227.
Documentation/docs-mobile/messages/index.md	Adds entries linking to the new XA docs pages.

Files not reviewed (1)

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

[jonathanpeppers]

@copilot address the code review comments where they are relevant and explain what you did in detail.

[Copilot]

@copilot address the code review comments where they are relevant and explain what you did in detail.

Addressed all relevant review comments in edc6d32:

1. XA4212 conflict — Renamed to XA4253 (unused code) since XA4212 is already used in XAJavaTypeScanner.cs for the IJavaObject without Java.Lang.Object error. Updated resource entries, JCWGenerator.cs, documentation file (renamed xa4212.md → xa4253.md), and index.md.

2. Non-deterministic type list ordering — Added .OrderBy(t => t, StringComparer.Ordinal) before string.Join so the type list in XA4217 messages is sorted and stable across runs/machines.

3. Double spaces after periods — Fixed all three doc files (xa4253.md, xa4217.md, xa4227.md) to use single spaces, matching the convention in other message docs.