Code generator namespace sanitization does not account for C# reserved identifiers

[dej4n]

For instance, if an assembly is named default, the code generator will produce a file with a syntax error, such as:

#pragma warning disable CS1591
[assembly: global::Orleans.ApplicationPartAttribute("default")]
[assembly: global::Orleans.ApplicationPartAttribute("Orleans.Core.Abstractions")]
[assembly: global::Orleans.ApplicationPartAttribute("Orleans.Serialization")]
[assembly: global::Orleans.ApplicationPartAttribute("Orleans.Core")]
[assembly: global::Orleans.Serialization.Configuration.TypeManifestProviderAttribute(typeof(OrleansCodeGen.default.Metadata_default))]
namespace OrleansCodeGen. default  {
    using global::Orleans.Serialization.Codecs;
    using global::Orleans.Serialization.GeneratedCodeHelpers;

    [global::System.CodeDom.Compiler.GeneratedCodeAttribute("OrleansCodeGen", "9.0.0.0"), global::System.ComponentModel.EditorBrowsableAttribute(global::System.ComponentModel.EditorBrowsableState.Never)]
    internal sealed class Metadata_default : global::Orleans.Serialization.Configuration.TypeManifestProviderBase
    {
        protected override void ConfigureInner(global::Orleans.Serialization.Configuration.TypeManifestOptions config)
        {
        }
    }
}
#pragma warning restore CS1591

Error at line: namespace OrleansCodeGen. default {

[ReubenBond]

Hi @dej4n, if you are willing to open a PR to fix this, it would be welcome, or a PR to introduce a clearer error when someone uses a reserved identifier.