feat: warn if using [contenthash] in filenames in development mode

[cseas]

Summary

Using [contenthash] in filenames in development mode would bloat memory. Added a warning to the console if [contenthash] is added to the filename in development mode.

Feature request: #9513

Gave a shot at implementing the feature. Please let me know if the warning should be added somewhere else in the codebase or if this needs an accompanying documentation update as well. I'd imagine the warning should go somewhere in the output docs as well: https://rspack.rs/config/output

Update: I noticed that the warning for this is already documented but it's too far down the page in another section and I just happened to stumble across it as I was reading the docs.

IMO it'd be easier to come across this warning if it came earlier in the output.filename docs, right where the usage of contenthash is first suggested:

Let me know, I'll move the warning up in the page if it makes sense.

Checklist

• Tests updated (or not required).
• Documentation updated (or not required).

[netlify]

✅ Deploy Preview for rspack canceled.

Built without sensitive environment variables

Name	Link
🔨 Latest commit	a37ad4b
🔍 Latest deploy log	https://app.netlify.com/projects/rspack/deploys/68389c319f29af000881e5aa

[CLAassistant]

All committers have signed the CLA.

[cseas]

@h-a-n-a Please review