New lint: replace `quasiquote` with `append` when possible

Here's something Resyntax ought to fix:

```
#lang resyntax/private/refactoring-test

test: "should replace quasiquote with append when equivalent"
--------------------
#lang racket
`(,@(mapping-get chunks id) ,@exprs)
--------------------
--------------------
#lang racket
(append (mapping-get chunks id) exprs)
--------------------
```

Found in racket/scribble#441.