Enable SemanticLogMessageFormatter as default logger formatter

Changed the default logger formatter from DefaultLogMessageFormatter to SemanticLogMessageFormatter to enable semantic logging support by default. This allows both positional {0} and named {PropertyName} templates to work out of the box.

Changes:
- Updated akka.conf to use SemanticLogMessageFormatter as default
- Added special case handling in Settings.cs for SemanticLogMessageFormatter singleton instance

All 62 existing logger tests pass, confirming backward compatibility with positional templates while enabling new semantic logging capabilities.

Author: Aaronontheweb

src/core/Akka/Actor/Settings.cs

@@ -182,6 +182,11 @@ public Settings(ActorSystem system, Config config, ActorSystemSetup setup)
                 {
                     LogFormatter = DefaultLogMessageFormatter.Instance;
                 }
+                // SPECIAL CASE - check for the semantic log message formatter, which does not have an empty constructor (it's private)
+                else if (logFormatType == typeof(SemanticLogMessageFormatter))
+                {
+                    LogFormatter = SemanticLogMessageFormatter.Instance;
+                }
                 else
                 {
                     try

src/core/Akka/Configuration/akka.conf

@@ -32,7 +32,7 @@ akka {
 
   # Specifies the formatter used to format log messages. Can be customized
   # to use a different logging implementation, such as Serilog.
-  logger-formatter = "Akka.Event.DefaultLogMessageFormatter, Akka"
+  logger-formatter = "Akka.Event.SemanticLogMessageFormatter, Akka"
 
   # Log level used by the configured loggers (see "loggers") as soon
   # as they have been started; before that, see "stdout-loglevel"