group by TypeSymbol

[ufcpp]

original source:

partial class Literal
{
    [StringLiteral.Utf8Attribute("a")]
    public static partial System.ReadOnlySpan<byte> A();
    [StringLiteral.Utf8Attribute("b")]
    public static partial System.ReadOnlySpan<byte> B();
}

current:

partial class Literal
{
    public static partial System.ReadOnlySpan<byte> A() => new byte[] { 97 };
}

partial class Literal
{
    public static partial System.ReadOnlySpan<byte> B() => new byte[] { 98 };
}

expected:

partial class Literal
{
    public static partial System.ReadOnlySpan<byte> A() => new byte[] { 97 };
    public static partial System.ReadOnlySpan<byte> B() => new byte[] { 98 };
}