nullable index

Author: Ben Chatelain

ObjectiveGit/GTIndexEntry.h

@@ -52,7 +52,7 @@ NS_ASSUME_NONNULL_BEGIN
 /// error - will be filled if an error occurs
 ///
 /// Returns the initialized object.
-- (instancetype)initWithGitIndexEntry:(const git_index_entry *)entry index:(GTIndex *)index error:(NSError **)error NS_DESIGNATED_INITIALIZER;
+- (instancetype)initWithGitIndexEntry:(const git_index_entry *)entry index:(nullable GTIndex *)index error:(NSError **)error NS_DESIGNATED_INITIALIZER;
 - (instancetype)initWithGitIndexEntry:(const git_index_entry *)entry;
 
 /// The underlying `git_index_entry` object.