Move hardcoded error string in PrepareAbiItems.cs to Resources.resx

[Copilot]

PrepareAbiItems.cs uses Log.LogError with a hardcoded string literal, bypassing the localization pipeline and lacking a proper XA#### error code.

Changes

• Properties/Resources.resx: Add XA0037 resource string (Unknown mode: {0})
• Properties/Resources.Designer.cs: Add corresponding generated property
• Tasks/PrepareAbiItems.cs: Replace Log.LogError with Log.LogCodedError
• Documentation/docs-mobile/messages/xa0037.md and index.md: Add documentation for the new XA0037 error code

// Before
Log.LogError ($"Unknown mode: {Mode}");

// After
Log.LogCodedError ("XA0037", Properties.Resources.XA0037, Mode);

Uses a dedicated, previously-unused error code XA0037 (the next free code after XA0036 in the XA0xxx range) rather than the generic XA0000. No existing localized coded message matched this internal "unknown mode" error, so a new code and resource string were added.

[jonathanpeppers]

@copilot the error code XA0000 is wrong, you should pick an unused code!

also verify there isn't an existing message we could use for this that is already localized and has a code.

[Copilot]

@copilot the error code XA0000 is wrong, you should pick an unused code!

also verify there isn't an existing message we could use for this that is already localized and has a code...

Switched to the dedicated unused code XA0037 (next free code after XA0036 in the XA0xxx range; XA0100 is the next existing one). I checked Resources.resx for an existing localized message to reuse and there isn't one that fits — this is an internal "should never happen" error specific to the PrepareAbiItems task's Mode, so no existing coded message matched. Added xa0037.md docs and an index entry as well.

[Copilot]

Pull request overview

This PR localizes a previously hardcoded error message in the PrepareAbiItems MSBuild task by introducing a new XA#### coded error (XA0037) backed by Resources.resx, and adds corresponding documentation for the new error code.

Changes:

• Added localized resource string XA0037 (“Unknown mode: {0}”) and the corresponding generated designer accessor.
• Updated PrepareAbiItems to log XA0037 via Log.LogCodedError instead of a hardcoded string.
• Added a new docs page for XA0037 and linked it from the messages index.

Reviewed changes

Copilot reviewed 4 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/Xamarin.Android.Build.Tasks/Tasks/PrepareAbiItems.cs	Switches from hardcoded Log.LogError to Log.LogCodedError using XA0037.
src/Xamarin.Android.Build.Tasks/Properties/Resources.resx	Adds the localized XA0037 message text and placeholder comment.
src/Xamarin.Android.Build.Tasks/Properties/Resources.Designer.cs	Adds the generated XA0037 property accessor.
Documentation/docs-mobile/messages/xa0037.md	Documents the new XA0037 error code and user guidance.
Documentation/docs-mobile/messages/index.md	Adds XA0037 to the error/warning reference index.
build-tools/banned-apis/banned-apis.targets	Reformatting/line-ending-only change (unrelated to XA0037 localization).

Files not reviewed (1)

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

[jonathanpeppers]

this is breaking CI in other places, so I'm inclined to merge this, it's causing weird things!