more detailed test assertion and change text to match new exception

Author: MV10

src/Serilog.Settings.Configuration/Settings/Configuration/ConfigurationReader.cs

@@ -226,7 +226,7 @@ IConfigurationArgumentValue GetArgumentValue(IConfigurationSection argumentSecti
                 // values as a result of reading multiple configuration sources.
                 if (argumentSection.Value != null && argumentSection.GetChildren().Any())
                     throw new InvalidOperationException(
-                        $"The value for the argument {argumentSection.Path} is assigned different value " +
+                        $"The value for the argument '{argumentSection.Path}' is assigned different value " +
                         "types in more than one configuration source. Ensure all configurations consistently " +
                         "use either a scalar (int, string, boolean) or a complex (array, section, list, " +
                         "POCO, etc.) type for this argument value.");

test/Serilog.Settings.Configuration.Tests/ConfigurationSettingsTests.cs

@@ -594,8 +594,8 @@ public void InconsistentComplexVsScalarArgumentValuesThrowsIOE()
             var ex = Assert.Throws<InvalidOperationException>(()
                 => ConfigFromJson(jsonDiscreteValue, jsonComplexValue));
 
-            Assert.Contains("Combined configuration sources", ex.Message);
-            Assert.Contains("pathFormat", ex.Message);
+            Assert.Contains("The value for the argument", ex.Message);
+            Assert.Contains("'Serilog:WriteTo:0:Args:pathFormat'", ex.Message);
         }
     }
 }