Updated all the TODO: comments in the Umbraco.Core project so they are all in the same format. ( // TODO: ) (#4220)

Also moved some of the comments so they are will work better / are not within Code Documentation comments

src/Umbraco.Core/Services/Implement/ScopeRepositoryService.cs

@@ -4,7 +4,7 @@ using Umbraco.Core.Scoping;
 
 namespace Umbraco.Core.Services.Implement
 {
-    // todo that one does not add anything = kill
+    // TODO: that one does not add anything = kill
     public abstract class ScopeRepositoryService : RepositoryService
     {
         protected ScopeRepositoryService(IScopeProvider provider, ILogger logger, IEventMessagesFactory eventMessagesFactory)