Ensure template files end with newline and add validation test

[Copilot]

Ensure template files end with newline and add validation test

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Fix template files missing trailing newlines

Description

GitHub tooling complains when files don't end with a newline. Fixed 26 template files across source code, CSS, and configuration files by adding trailing newlines.

Added NewlineEndingTest:

• Validates all template files end with newline (LF/0x0a)
• Mirrors existing ByteOrderMarkTest pattern
• Excludes third-party libraries (wwwroot/lib/*) and auto-generated localization files (.template.config/localize/*)

Fixed files:

• 4 source files: .fs, .razor
• 5 CSS files
• 17 configuration files: template.json, dotnetcli.host.json, ide.host.json, strings.json

Original prompt

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This section details on the original issue you should resolve

<issue_title>NIT: Returns in project template files</issue_title>
<issue_description>### Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

NIT, so only if interested ......

GH complains about files not ending on a blank line (i.e., LF on the last code line). The BWA template has at least one example ...

https://github.com/dotnet/aspnetcore/blob/main/src/ProjectTemplates/Web.ProjectTemplates/content/BlazorWeb-CSharp/BlazorWebCSharp.1/Components/Pages/NotFound.razor

[Edit the file to witness it.]

Do you want to go through and confirm/update any files for this?

Expected Behavior

No response

Steps To Reproduce

No response

Exceptions (if any)

No response

.NET Version

No response

Anything else?

No response</issue_description>

<agent_instructions>Prepare a PR. Be sensible and avoid any file that shouldn't get this treatment, indicate so in your summary (which files you didn't change and the reason). We should also include a check similar to the one that we have for BOM on files.</agent_instructions>

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

@ilonatommy @guardrex, just to clarify, are you suggesting here that we should always have a blank line in our template files? @javiercn @guardrex thanks for the clarification.

I think if this is the case, we would probably treat it similarly to the BOM and make sure that every file has the line ending and that we have tests that validate they get generated with it.

@guardrex any examples where GH is complaining? I imagine you mean copilot.</comment_new>
<comment_new>@javiercn
Hmm, not sure if this is a manual thing or if has been caused by .gitattributes.</comment_new>

• Fixes NIT: Returns in project template files #64752

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