Fix more 9 0 delete behaviour

[mipmip]

I think I got them all now.

$ grep delete src -r | grep JSON| grep -v Bool | grep -v "#"

src/gitlab/client/merge_request.cr:      def delete_merge_request(project_id : Int32, merge_request_id : Int32) : JSON::Any
src/gitlab/client/branch.cr:      def delete_branch(project_id : Int32, branch : String) : JSON::Any
src/gitlab/client/note.cr:      def delete_issue_note(project_id : Int32, issue_id : Int32, note_id : Int32) : JSON::Any
src/gitlab/client/note.cr:      def delete_snippet_note(project_id : Int32, snippet_id : Int32, note_id : Int32) : JSON::Any
src/gitlab/client/note.cr:      def delete_merge_request_note(project_id : Int32, merge_request_id : Int32, note_id : Int32) : JSON::Any
src/gitlab/client/project.cr:      def project_delete_custom_attribute(project_id : Int32, key : String) : JSON::Any
src/gitlab/client/issue.cr:      def delete_issue(project_id : Int32, issue_id : Int32) : JSON::Any
src/gitlab/client/group.cr:      def delete_group(group_id : Int32) : JSON::Any
src/gitlab/client/group.cr:      def group_delete_custom_attribute(group_id : Int32, key : String) : JSON::Any
src/gitlab/client/label.cr:      def delete_label(project_id : Int32, name : String) : JSON::Any

[icyleaf]

Great works!