add includeKeys convenience to PFQuery

Parse/Internal/Query/State/PFMutableQueryState.h

@@ -65,6 +65,7 @@
 ///--------------------------------------
 
 - (void)includeKey:(NSString *)key;
+- (void)includeKeys:(NSArray<NSString *> *)keys;
 
 ///--------------------------------------
 #pragma mark - Selected Keys

Parse/Internal/Query/State/PFMutableQueryState.m

@@ -151,6 +151,14 @@ - (void)includeKey:(NSString *)key {
     }
 }
 
+- (void)includeKeys:(NSArray<NSString *> *)keys {
+    if (!_includedKeys) {
+        _includedKeys = [NSMutableSet setWithArray:keys];
+    } else {
+        [_includedKeys addObjectsFromArray:keys];
+    }
+}
+
 ///--------------------------------------
 #pragma mark - Selected Keys
 ///--------------------------------------

Parse/PFQuery.h

@@ -83,7 +83,7 @@ typedef void (^PFQueryArrayResultBlock)(NSArray<PFGenericObject> *_Nullable obje
 ///--------------------------------------
 
 /**
- Make the query include PFObjects that have a reference stored at the provided key.
+ Make the query include `PFObject`s that have a reference stored at the provided key.
 
  This has an effect similar to a join.  You can use dot notation to specify which fields in
  the included object are also fetch.
@@ -94,6 +94,15 @@ typedef void (^PFQueryArrayResultBlock)(NSArray<PFGenericObject> *_Nullable obje
  */
 - (instancetype)includeKey:(NSString *)key;
 
+/**
+ Make the query include `PFObject`s that have a reference stored at the provided keys.
+
+ @param keys The keys to load child `PFObject`s for.
+
+ @return The same instance of `PFQuery` as the receiver. This allows method chaining.
+ */
+- (instancetype)includeKeys:(NSArray<NSString *> *)keys;
+
 /**
  Make the query restrict the fields of the returned `PFObject`s to include only the provided keys.
 

Parse/PFQuery.m

@@ -405,6 +405,12 @@ - (instancetype)includeKey:(NSString *)key {
     return self;
 }
 
+- (instancetype)includeKeys:(NSArray<NSString *> *)keys {
+    [self checkIfCommandIsRunning];
+    [self.state includeKeys:keys];
+    return self;
+}
+
 ///--------------------------------------
 #pragma mark - Select
 ///--------------------------------------