Fix for trivia not preserved after string interpolation conversion

[AppAppWorks]

fix an issue in #1551

My bad, I should've tested the code action more thoroughly. The leading trivia of the source SequenceExprSyntax is not carried over to the new string literal, resulting in this:

<code block A>
"" + value + ""
<code block B>

->

<code block A>"\(value)"
<code block B>

This fix will preserve the leading trivia, i.e.

<code block A>
"\(value)"
<code block B>

[ahoppen]

How was // code block A preserved before this change if the leading trivia of the code block weren’t preserved? Or did you mean for // code block A to be a statement?

Should we also retain the trailing trivia from syntax in the same way?

[AppAppWorks]

Yeah, // code block A was meant for a statement instead of a comment, I've changed that in the description above.

AFAIK, string literals don't have trailing trivia, and trailing trivia of any non-string-literal component will be converted and moved into the string interpolation, so the trailing trivia of syntax has been preserved in this way.

[ahoppen]

What about "a" + b + "c" / * some comment */? In that case /* some comment */ should be trailing trivia for the ".

[ahoppen]

@swift-ci Please test

[ahoppen]

@swift-ci Please test Windows

[ahoppen]

Looks like this line has trailing whitespace. Could you run swift-format on your changes? https://github.com/swiftlang/sourcekit-lsp/blob/main/CONTRIBUTING.md#formatting

[AppAppWorks]

Done, please test again.

[ahoppen]

@swift-ci Please test

[ahoppen]

@swift-ci Please test Windows