Fix compile issue with escaped characters in logging generator message

src/libraries/Microsoft.Extensions.Logging.Abstractions/gen/LoggerMessageGenerator.Emitter.cs

@@ -152,7 +152,7 @@ private void GenStruct(LoggerMethod lm, string nestedIndentation)
 ");
                 GenVariableAssignments(lm, nestedIndentation);
                 _builder.Append($@"
-                {nestedIndentation}return $""{lm.Message}"";
+                {nestedIndentation}return $""{ConvertEndOfLineAndQuotationCharactersToEscapeForm(lm.Message)}"";
             {nestedIndentation}}}
 ");
                 _builder.Append($@"

src/libraries/Microsoft.Extensions.Logging.Abstractions/tests/Microsoft.Extensions.Logging.Generators.Tests/LoggerMessageGeneratedCodeTests.cs

@@ -194,6 +194,14 @@ public void MessageTests()
             Assert.Equal(LogLevel.Trace, logger.LastLogLevel);
             Assert.Equal(6, logger.LastEventId.Id);
             Assert.Equal(1, logger.CallCount);
+
+            logger.Reset();
+            MessageTestExtensions.M7(logger, LogLevel.Trace, "p", "q");
+            Assert.Null(logger.LastException);
+            Assert.Equal("\"p\" -> \"q\"", logger.LastFormattedString);
+            Assert.Equal(LogLevel.Trace, logger.LastLogLevel);
+            Assert.Equal(7, logger.LastEventId.Id);
+            Assert.Equal(1, logger.CallCount);
         }
 
         [Fact]

src/libraries/Microsoft.Extensions.Logging.Abstractions/tests/Microsoft.Extensions.Logging.Generators.Tests/TestClasses/MessageTestExtensions.cs

@@ -35,5 +35,8 @@ internal static partial class MessageTestExtensions
 
         [LoggerMessage(EventId = 6, Message = "")]
         public static partial void M6(ILogger logger, LogLevel level);
+
+        [LoggerMessage(EventId = 7, Message = "\"{Value1}\" -> \"{Value2}\"")]
+        public static partial void M7(ILogger logger, LogLevel logLevel, string value1, string value2);
     }
 }