Add note to docs about `sharp` memory usage on default Linux setup (#31919)
Add note to docs about `sharp` memory usage on default Linux setup (#31919)

It's fairly opaque to the user that there are problems with `sharp` in an out-of-the-box Linux environment, and so if `sharp` is going to be explicitly recommended for non-Vercel production environments then I think it's a good idea to make sure people are aware of the possible issues.

My vanilla Heroku deployment was using wild amounts of memory until I found the details in the sharp docs about how to configure the memory allocator, so signposting this a bit better should help prevent issues in future.



## Bug

- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`

## Feature

- [ ] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`

## Documentation / Examples

- [ ] Make sure the linting passes by running `yarn lint`


Co-authored-by: Lee Robinson <565ca9f7a872cfed76f7827de2fbb0f26a53dfdf@users.noreply.github.com>
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