fix 'Unit StdbNone' syntax error

Author: Centril

crates/cli/src/subcommands/generate/csharp.rs

@@ -771,7 +771,7 @@ pub fn autogen_csharp_globals(ctx: &GenCtx, items: &[GenItem], namespace: &str)
         for reducer_name in &reducer_names {
             writeln!(output, "{reducer_name} {reducer_name},");
         }
-        writeln!(output, "Unit StdbNone,");
+        writeln!(output, "Unit StdbNone");
     }
     writeln!(output, ")>;");