force type stability of _invoked_shouldlog & friends for non-concrete loggers (#41863)

Author: thchr

base/logging.jl

@@ -79,15 +79,15 @@ function _invoked_shouldlog(logger, level, _module, group, id)
         shouldlog,
         Tuple{typeof(logger), typeof(level), typeof(_module), typeof(group), typeof(id)},
         logger, level, _module, group, id
-    )
+    )::Bool
 end
 
 function _invoked_min_enabled_level(@nospecialize(logger))
-    return invoke(min_enabled_level, Tuple{typeof(logger)}, logger)
+    return invoke(min_enabled_level, Tuple{typeof(logger)}, logger)::LogLevel
 end
 
 function _invoked_catch_exceptions(@nospecialize(logger))
-    return invoke(catch_exceptions, Tuple{typeof(logger)}, logger)
+    return invoke(catch_exceptions, Tuple{typeof(logger)}, logger)::Bool
 end
 
 """