doc: update Buffer.allocUnsafe description

PR-URL: #48183
Fixes: #42821
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

doc/api/buffer.md

@@ -807,10 +807,9 @@ A `TypeError` will be thrown if `size` is not a number.
 
 The `Buffer` module pre-allocates an internal `Buffer` instance of
 size [`Buffer.poolSize`][] that is used as a pool for the fast allocation of new
-`Buffer` instances created using [`Buffer.allocUnsafe()`][],
-[`Buffer.from(array)`][], [`Buffer.concat()`][], and the deprecated
-`new Buffer(size)` constructor only when `size` is less than or equal
-to `Buffer.poolSize >> 1` (floor of [`Buffer.poolSize`][] divided by two).
+`Buffer` instances created using [`Buffer.allocUnsafe()`][], [`Buffer.from(array)`][],
+and [`Buffer.concat()`][] only when `size` is less than or equal to
+`Buffer.poolSize >> 1` (floor of [`Buffer.poolSize`][] divided by two).
 
 Use of this pre-allocated internal memory pool is a key difference between
 calling `Buffer.alloc(size, fill)` vs. `Buffer.allocUnsafe(size).fill(fill)`.