Fix confusing syntax in RZ9979 error message for code blocks in attributes

[Copilot]

Summary of the changes

Error RZ9979 displayed '@{{ {0} }}' and {{... }} with spaces around placeholders, suggesting incorrect syntax to users. Changed to '@{{{0}}}' and {{...}} without spaces.

• Updated error message in ComponentDiagnosticFactory.cs: '@{{ {0} }}' → '@{{{0}}}' and {{... }} → {{...}}
• Reverted previous incorrect changes to RZ1029 (Resources.resx and 8 test baseline files)

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Confused by error message regarding attribute syntax</issue_title>
<issue_description>I’ve just started to play around with Blazor and tried to write this code in a .razor-file:

<span class="@if(sortType != 0) { <text>btn-primary</text> } else { <text>btn-success</text> }">

Yes, not very elegant :-) Either way, I got this error message that confuses me:

Code blocks delimited by '@{...}' like '@{ if(sortType != 0) { } }' for attributes are no longer supported These features have been changed to use attribute syntax. Use 'attr="@(x => {... }"'.

I’ve tried to rewrite me code to use lambda expression as suggested, but whatever I do a get an error message. Is this possible in this case? I’ve noticed that a lambda expression works fine if the attribute is @onclick.

If I rewrite my code like this it works, but that is not was the error message suggest:

<span class="btn @(sortType != 0 ? "btn-primary" : "btn-success")">

</issue_description>

Comments on the Issue (you are @copilot in this section)

@ We've moved this issue to the Backlog milestone. This means that it is not going to be worked on for the coming release. We will reassess the backlog following the current release and consider this item at that time. To learn more about our issue management process and to have better expectation regarding different types of issues you can read our [Triage Process](https://github.com/dotnet/aspnetcore/blob/master/docs/TriageProcess.md). @ We've moved this issue to the Backlog milestone. This means that it is not going to be worked on for the coming release. We will reassess the backlog following the current release and consider this item at that time. To learn more about our issue management process and to have better expectation regarding different types of issues you can read our [Triage Process](https://github.com/dotnet/aspnetcore/blob/main/docs/TriageProcess.md).

• Fixes Confused by error message regarding attribute syntax #12190

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[chsienki]

@copilot This is the incorrect message to change. Undo the previous work. The message you need to change is RZ9979

[Copilot]

@copilot This is the incorrect message to change. Undo the previous work. The message you need to change is RZ9979

Reverted the changes to RZ1029 and fixed RZ9979 instead. Changed '@{{ {0} }}' to '@{{{0}}}' and '{{... }}' to '{{...}}' in ComponentDiagnosticFactory.cs (commit 5a8668b).