RFR: 8318693: Fix rendering for code blocks nested under list items in building.md

[Conor Cleary]

On Tue, 24 Oct 2023 02:45:41 GMT, Zixian Cai <zcai at openjdk.org> wrote:

> Currently, code blocks under list items are rendered in a single line, which is difficult to read and copy.
> For example, see below from https://htmlpreview.github.io/?https://raw.githubusercontent.com/openjdk/jdk/master/doc/building.html#building-for-risc-v 
> ![Screenshot 2023-10-24 at 13 46 03](https://github.com/openjdk/jdk/assets/2891235/fc9f1472-74a8-451f-b797-66973b4ec81c)
> 
> After fix
> ![Screenshot 2023-10-24 at 13 47 49](https://github.com/openjdk/jdk/assets/2891235/b11027c1-bbdc-47c2-b209-976b86865fcc)

Marked as reviewed by ccleary (Committer).

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PR Review: https://git.openjdk.org/jdk/pull/16332#pullrequestreview-1695051051