Adding comments for testSignInWithCredentialSuccess

Author: aiwenisevan

FirebaseAuth/Tests/Unit/FIRAuthTests.m

@@ -1424,7 +1424,7 @@ - (void)testSignInWithGoogleCredentialFailure {
 /** @fn testSignInWithOAuthCredentialWithDisplayNameSuccess
     @brief Tests the flow of a successful @c signInWithCredential:completion: call
         with an Apple Sign-In credential.
-    This method differntiate the testSignInWithCredentialSuccess only in verifying displayName
+    This method differntiates the testSignInWithCredentialSuccess only in verifying displayName
  */
 - (void)testSignInWithOAuthCredentialWithDisplayNameSuccess {
   OCMExpect([_mockBackend verifyAssertion:[OCMArg any] callback:[OCMArg any]])