Programgen emits "@" string literals - left over from C#

What happened?

		// This string does contain newlines, so we'll generate a verbatim string literal. Quotes will be escaped
		// in conformance with
		// https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/language-specification/lexical-structure
		g.Fgen(w, "@\"")
		g.Fgen(w, g.escapeString(v, true, false))
		g.Fgen(w, "\"")

Perhaps this code or something else ends up generating something really strange looking:

https://github.com/pulumi/pulumi-java/runs/6327889540?check_suite_focus=true#step:11:62

Which gets improperly included in javadoc and breaks compilation.

                     @( string.Join(",", DateTime.UtcNow, context.Deployment.ServiceName, context.RequestId, context.Request.IpAddress, context.Operation.Name) ) 
    ```

`DateTime.UtcNow` is also C#-ism.



### Steps to reproduce

See 
https://github.com/pulumi/pulumi-java/runs/6327889540?check_suite_focus=true#step:11:62


### Expected Behavior

Working code generated

### Actual Behavior

Broken code generated

### Versions used

I believe this is coming from pkg/0.1.0 version of programgen.

### Additional context

_No response_

### Contributing

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To contribute a fix for this issue, leave a comment (and link to your pull request, if you've opened one already). 

Start with the programgen code that emits string literals and inspect the generated output from the linked run, especially the leading @ and DateTime.UtcNow. Reproduce the failure using the referenced run or generated Java code, then verify that the output contains valid Java and compiles without malformed Javadoc.