Remove bogus xlf tag

This was causing the failures on Aleksey's machine in #80353. Something about his machine is doing this, where the Spanish leg in CI is not seeing the same failure.

Author: 333fred

src/Compilers/CSharp/Portable/CSharpResources.resx

@@ -8194,6 +8194,6 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
   </data>
   <data name="ERR_MethodImplAttributeAsyncCannotBeUsed" xml:space="preserve">
     <value>'MethodImplAttribute.Async' cannot be manually applied to methods. Mark the method 'async'.</value>
-    <remarks>'MethodImplAttribute.Async' and 'async' are not localizable.</remarks>
+    <comment>'MethodImplAttribute.Async' and 'async' are not localizable.</comment>
   </data>
-</root>
+</root>