Include inner message in exception thrown from JS thread (#378)

Author: jasongin

src/NodeApi/JSException.cs

@@ -43,7 +43,7 @@ public JSException(JSError error) : base(error.Message)
     /// This constructor must be called while still on the JS thread.
     /// </remarks>
     internal JSException(Exception innerException)
-        : this("Exception thrown from JS thread. See inner exception for details.", innerException)
+        : this("Exception thrown from JS thread: " + innerException?.Message, innerException)
     {
         JSException? innerJSException = innerException as JSException;
         JSValue? jsError = innerJSException?.Error?.Value;

test/NodejsEmbeddingTests.cs

@@ -214,7 +214,7 @@ public void ErrorPropagation()
             });
         });
 
-        Assert.StartsWith("Exception thrown from JS thread.", exception.Message);
+        Assert.Equal("Exception thrown from JS thread: test", exception.Message);
         Assert.IsType<JSException>(exception.InnerException);
 
         exception = (JSException)exception.InnerException;