Fix RCS1077 formatting when converting Select().ToList() to ConvertAll()

[MattFromRVA]

Fixes #1728

[josefpihrt]

Nice fix — the root cause (the new node inheriting the Select invocation's trailing trivia, which carried the newline before .ToList()) is correctly addressed by anchoring to toListInvocation.GetTrailingTrivia(), and it stays backward-compatible with the single-line case. A couple of inline comments below; one I'd suggest resolving before merge.

Test coverage: could we add a case for a single-line // comment in the removed segment (see the inline comment on the if), and optionally one with an IReadOnlyList<...> target to mirror the exact repro in #1728? The current tests only cover /* */, which is what lets the // case slip through.

[josefpihrt]

This branch strips all whitespace/EOL trivia and reattaches surviving comments inline. That's fine for block comments, but a single-line // comment has no terminating newline of its own — the newline is separate EndOfLineTrivia, which gets stripped here. So this input:

var x = items
    .Select(f => f.ToString()) // keep this
    .ToList();

would become:

var x = items
    .ConvertAll(f => f.ToString())// keep this;

…where the ; is now commented out → compile error. Could we preserve a trailing newline when the salvaged trivia ends in a single-line comment (or otherwise guard against it)? A //-comment variant of Test_CallConvertAllInsteadOfSelectAndToList_PreservesCommentInRemovedSegment would reproduce it.

[josefpihrt]

Nit: both branches converge on ... .Concat(toListInvocation.GetTrailingTrivia()) — when there are no comments the Where yields nothing, so this collapses to a single path:

IEnumerable<SyntaxTrivia> comments = removedTrivia.Where(f => !f.IsWhitespaceOrEndOfLineTrivia());
newInvocationExpression = newInvocationExpression.WithTrailingTrivia(
    comments.Concat(toListInvocation.GetTrailingTrivia()));

Behavior-equivalent and drops the branch. Also worth materializing removedTrivia with .ToList() since it's currently enumerated multiple times.