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
Checklist
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make -j4 test
(UNIX), orvcbuild test
(Windows) passes -
documentation is changed or added -
commit message follows commit guidelines