-Fix exception message spelling mistake

Author: JamesNK

Src/Newtonsoft.Json.Tests/JsonConvertTest.cs

@@ -257,7 +257,7 @@ public void ObjectToString()
     }
 
     [Test]
-    [ExpectedException(typeof(JsonReaderException), ExpectedMessage = "After parsing a value an unexpected character was encoutered: t. Line 1, position 20.")]
+    [ExpectedException(typeof(JsonReaderException), ExpectedMessage = "After parsing a value an unexpected character was encountered: t. Line 1, position 20.")]
     public void TestInvalidStrings()
     {
       string orig = @"this is a string ""that has quotes"" ";

Src/Newtonsoft.Json/Bson/BsonBinaryWriter.cs

@@ -58,7 +58,7 @@ private void WriteTokenInternal(BsonToken t)
             foreach (BsonToken c in value)
             {
               _writer.Write((sbyte)c.Type);
-              WriteString(index.ToString(CultureInfo.InvariantCulture), Encoding.GetByteCount(index.ToString(CultureInfo.InvariantCulture)), null);
+              WriteString(index.ToString(CultureInfo.InvariantCulture), MathUtils.IntLength(index), null);
               WriteTokenInternal(c);
               index++;
             }

Src/Newtonsoft.Json/JsonTextReader.cs

@@ -409,7 +409,7 @@ private bool ParsePostValue(char currentChar)
             }
             else
             {
-              throw CreateJsonReaderException("After parsing a value an unexpected character was encoutered: {0}. Line {1}, position {2}.", currentChar, _currentLineNumber, _currentLinePosition);
+              throw CreateJsonReaderException("After parsing a value an unexpected character was encountered: {0}. Line {1}, position {2}.", currentChar, _currentLineNumber, _currentLinePosition);
             }
             break;
         }