Improve formatting of pattern matching (IsPatternExpression, BinaryPattern, etc)

[belav]

Should IsPatterns break like this?

        var useLine =
            node.OperatorToken.Kind() is SyntaxKind.BarBarToken
                or SyntaxKind.BarToken
                or SyntaxKind.AmpersandAmpersandToken
                or SyntaxKind.AmpersandToken
                or SyntaxKind.PlusToken;

They currently break like

        var useLine =
            node.OperatorToken.Kind()
                is SyntaxKind.BarBarToken
                    or SyntaxKind.BarToken
                    or SyntaxKind.AmpersandAmpersandToken
                    or SyntaxKind.AmpersandToken
                    or SyntaxKind.PlusToken;

[belav]

See also

        if (
            MethodKind
                is not (MethodKind.Ordinary
                    or MethodKind.LocalFunction)
        ) {
            return;
        }

Which could break like this and still be below the print width

        if (
            MethodKind
                is not (MethodKind.Ordinary or MethodKind.LocalFunction)
        ) {
            return;
        }

[belav]

I believe we want to treat BinaryPatterns more like BinaryExpressions. That requires flattening out the patterns into an array, and then grouping them.

[respel]

var useLine =
node.OperatorToken.Kind() is SyntaxKind.BarBarToken
or SyntaxKind.BarToken
or SyntaxKind.AmpersandAmpersandToken
or SyntaxKind.AmpersandToken
or SyntaxKind.PlusToken;

This doesn't look like valid syntax to me. Maybe I'm missing something.

[belav]

It is using pattern matching, I think some of this wasn't introduced until c# 9
https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/operators/patterns#logical-patterns

[belav]

BinaryPatterns are essentially the same as a BinaryExpression and should be printed the same.
They have a Left, OperatorToken and Right.
BinaryPatterns are not currently indented, and things like IsPattern do the indentation, which I don't believe is the way it should be handled.
If we keep IsPattern indenting, then SwitchExpression will also need to indent.

See #37, possibly do this at the same time.

Mixed example

if (
      nestedExpression.Children[j]
          is IntermediateToken cSharpToken && cSharpToken.IsCSharp
  ) { }

// should be

if (
    nestedExpression.Children[j]
        is IntermediateToken cSharpToken
    && cSharpToken.IsCSharp
) { }

[belav]

Another edge case

            if (
                !(node
                    is PrefixUnaryExpressionSyntax { Operand: ParenthesizedExpressionSyntax { Expression: IsPatternExpressionSyntax { Pattern: DeclarationPatternSyntax, } isPattern, }, } notExpression)
            ) {
                return;
            }

[belav]

Probably related

            return rightNode switch
            {
                InitializerExpressionSyntax => Layout.BasicConcatWithoutLine,
                ConditionalExpressionSyntax { Condition: BinaryExpressionSyntax }
                or BinaryExpressionSyntax
                or InterpolatedStringExpressionSyntax
                or IsPatternExpressionSyntax
                or LiteralExpressionSyntax
                or QueryExpressionSyntax
                or StackAllocArrayCreationExpressionSyntax
                or ImplicitObjectCreationExpressionSyntax
                  => Layout.BreakAfterOperator,
                _ => Layout.Fluid
            };