Link from CONTRIBUTING.md to prettier-plugin-sql-cst

Author: nene

CONTRIBUTING.md

@@ -1,5 +1,8 @@
 # Development
 
+First consider if you might instead want to contribute to [prettier-plugin-sql-cst][] instead,
+as SQL Formatter is mostly in maintenance mode.
+
 ## Setup
 
 Run `yarn` after checkout to install all dependencies.
@@ -18,3 +21,5 @@ For those who have admin access on the repo, the new release publish flow is as
 
 - `npm run release` (bumps version, git tag, git release, npm release) (does not work with `yarn`).
 - `git subtree push --prefix static origin gh-pages` (pushes demo page to GH pages)
+
+[prettier-plugin-sql-cst]: https://github.com/nene/prettier-plugin-sql-cst