docs: fix license headers and file identifications #281
Description
The style for header of each file is not consistent across all files in the project. The copyright date isn't updated to 2022. We should figure out a template for all of our file headers and fix this.
This is the style mostly found in this project:
//===----------------------------------------------------------------------===//
//
// BusTub
//
// rid.h
//
// Identification: src/include/common/rid.h
//
// Copyright (c) 2015-2019, Carnegie Mellon University Database Group
//
//===----------------------------------------------------------------------===//