Fix message for InvalidProtocolBufferException

csharp/src/Google.Protobuf/InvalidProtocolBufferException.cs

@@ -61,7 +61,7 @@ namespace Google.Protobuf
         {
             return new InvalidProtocolBufferException(
                 "While parsing a protocol message, the input ended unexpectedly " +
-                "in the middle of a field.  This could mean either than the " +
+                "in the middle of a field.  This could mean either that the " +
                 "input has been truncated or that an embedded message " +
                 "misreported its own length.");
         }

javanano/src/main/java/com/google/protobuf/nano/InvalidProtocolBufferNanoException.java

@@ -48,7 +48,7 @@ public class InvalidProtocolBufferNanoException extends IOException {
   static InvalidProtocolBufferNanoException truncatedMessage() {
     return new InvalidProtocolBufferNanoException(
       "While parsing a protocol message, the input ended unexpectedly " +
-      "in the middle of a field.  This could mean either than the " +
+      "in the middle of a field.  This could mean either that the " +
       "input has been truncated or that an embedded message " +
       "misreported its own length.");
   }