Merge pull request #43 from ccho-mongodb/120220-fix

correction in auth mech

Author: Chris Cho

source/fundamentals/auth.txt

@@ -273,7 +273,7 @@ mechanism:
    .. tab::
       :tabid: MongoCredential
 
-      To specify the default authentication mechanism using the
+      To specify the ``MONGODB-AWS`` authentication mechanism using the
       ``MongoCredential`` class, use the
       :java-docs:`createAwsCredential() </apidocs/mongodb-driver-core/com/mongodb/MongoCredential.html#createAwsCredential(java.lang.String,char%5B%5D)>`
       method. Your code to instantiate a ``MongoClient`` should resemble the