Typo and doc fix

src/objective-c/GRPCClient/GRPCCall.h

@@ -228,7 +228,8 @@ extern id const kGRPCTrailersKey;
                                handler:(id<GRPCResponseHandler>)handler
                            callOptions:(GRPCCallOptions *)callOptions NS_DESIGNATED_INITIALIZER;
 /**
- * Convevience initializer for a call that uses default call options.
+ * Convenience initializer for a call that uses default call options (see GRPCCallOptions.m for
+ * the default options).
  */
 - (instancetype)initWithRequestOptions:(GRPCRequestOptions *)requestOptions
                                handler:(id<GRPCResponseHandler>)handler;

src/objective-c/GRPCClient/GRPCCallOptions.m

@@ -18,6 +18,7 @@
 
 #import "GRPCCallOptions.h"
 
+// The default values for the call options.
 static NSString *const kDefaultServerAuthority = nil;
 static const NSTimeInterval kDefaultTimeout = 0;
 static NSDictionary *const kDefaultInitialMetadata = nil;