RFR: 8348180: Remove mention of include of precompiled.hpp from the HotSpot Style Guide

[Erik Österlund]

On Tue, 21 Jan 2025 12:29:33 GMT, Stefan Karlsson <stefank at openjdk.org> wrote:

> [JDK-8347909](https://bugs.openjdk.org/browse/JDK-8347909) removed the need for HotSpot devs to include the precompiled.hpp. This is the PR to reflect that.
> 
> I know that there is some process around updating the style guide, but I can't find it, so I'm starting with a plain PR.

Seems reasonable.

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Marked as reviewed by eosterlund (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/23210#pullrequestreview-2564522660