doc: improve doc v8.getHeapSpaceStatistics() 'GetHeapSpaceStatistics'

Link replaced in v8 getHeapSpaceStatistics function because it was
showing 404 page not found.

Fixes: https://github.com/nodejs/node/issues/31181

PR-URL: https://github.com/nodejs/node/pull/31274


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: David Carlier <devnexen@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>