Updating comments per the C++ core guidelines and removing trailing whitespace (#194)

Fixed comments that were inconsistent with the style guidelines described in C++ core guidelines and the modern C++/WinRT language projections and removed trailing whitespace.

Inserted a space after the beginning of the comment so the text wasn't touching the // on all occurrences.

Removed all occurrences of trailing whitespace

src/CalcViewModel/DataLoaders/CurrencyDataLoader.cpp

@@ -203,7 +203,7 @@ void CurrencyDataLoader::LoadData()
                 }
             }
 
-            co_return didLoad;            
+            co_return didLoad;
         }).then([this](bool didLoad)
         {
             UpdateDisplayedTimestamp();
@@ -329,7 +329,7 @@ task<bool> CurrencyDataLoader::TryLoadDataFromCacheAsync()
         {
             loadComplete = co_await TryLoadDataFromWebAsync();
         }
-        
+
         if (!loadComplete)
         {
             loadComplete = co_await TryFinishLoadFromCacheAsync();