parser: fix some deadlinks (#48539)

close #41241

pkg/parser/README.md

@@ -7,13 +7,13 @@
 
 The goal of this project is to build a Golang parser that is fully compatible with MySQL syntax, easy to extend, and high performance. Currently, features supported by parser are as follows:
 
-- Highly compatible with MySQL: it supports almost all features of MySQL. For the complete details, see [parser.y](https://github.com/pingcap/tidb/blob/master/parser/parser.y) and [hintparser.y](https://github.com/pingcap/tidb/blob/master/parser/hintparser.y).
+- Highly compatible with MySQL: it supports almost all features of MySQL. For the complete details, see [parser.y](https://github.com/pingcap/tidb/blob/master/pkg/parser/parser.y) and [hintparser.y](https://github.com/pingcap/tidb/blob/master/pkg/parser/hintparser.y).
 - Extensible: adding a new syntax requires only a few lines of Yacc and Golang code changes. As an example, see [PR-680](https://github.com/pingcap/parser/pull/680/files).
 - Good performance: the parser is generated by goyacc in a bottom-up approach. It is efficient to build an AST tree with a state machine.
 
 ## How to use it
 
-Please read the [quickstart](https://github.com/pingcap/tidb/blob/master/parser/docs/quickstart.md).
+Please read the [quickstart](https://github.com/pingcap/tidb/blob/master/pkg/parser/docs/quickstart.md).
 
 ## Future
 
@@ -32,8 +32,6 @@ If you have any questions, feel free to discuss in sig-ddl. Here are the steps t
 1. Join [TiDB Slack community](https://pingcap.com/tidbslack/), and then
 2. Join [sig-ddl Slack channel](https://slack.tidb.io/invite?team=tidb-community&channel=sig-ddl&ref=github_sig).
 
-If you want to join as a special interest group member, see [DDL Special Interest Group](https://github.com/pingcap/community/tree/master/special-interest-groups/sig-ddl).
-
 ## Users
 
 These projects use this parser. Please feel free to extend this list if you