RFR: Add start on a section about logging

[Jesper Wilhelmsson]

On Fri, 17 Dec 2021 14:54:50 GMT, Ludvig Janiuk <duke at openjdk.java.net> wrote:

> It's hard to find information on how one should write logging code in Hotspot. This PR is only a first attempt at pointing the reader in the right direction, but a lot could be added in the future:
>  * In which contexts can one not use unified logging?
>  * How much should one log?
>  * What other logging strategies are there?

Thank you for adding this! This is a good start of an important section.

src/index.md line 1310:

> 1308: After a failure is handled by excluding a test, the main JBS issue should be re-triaged and possibly given a new priority. This should be handled by the standard triage process. A test exclusion results in an outage in our testing. This outage should be taken into consideration when triaging, in addition to the impact of the bug itself.
> 1309: 
> 1310: # Adding new code in Hotspot

HotSpot should be written with capital S. More occurrences later.

I wonder if we should call this section something more generic, like "HotSpot Development" so that it can host more than just addition of code.

src/index.md line 1320:

> 1318: :::
> 1319: 
> 1320: While developing your fix, your might want your code to output some diagnostic information. You might even want to leave some logging output on in the code you check in, to facilitate future diagnostics.

"output on in" -> "output in" ?

src/index.md line 1342:

> 1340: ~~~
> 1341: 
> 1342: At the time of writing, the different log levels can be found in `src/hotspot/share/logging/log.hpp`.

Please link the source file to the GitHub source.

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Changes requested by jwilhelm (Lead).

PR: https://git.openjdk.java.net/guide/pull/70