[gatsby] Customize sourcemap content

[lobsterkatie]

The gatsby docs use the generic JS sourcemap content (see here). Our gatsby SDK runs the webpack plugin itself, and our docs should reflect that.

For comparison, check out the nextjs surcemap docs. (Our nextjs SDK similarly runs the webpack plugin itself.)

[getsentry-release]

Routing to @getsentry/team-web-sdk-frontend for triage. ⏲️

[mydea]

Why was this issue closed?

This issue hasn't been touched recently and no longer seems relevant. Hence, we're closing it to maintain a clean and transparent backlog.

Please feel free to leave a comment if you think this issue should be reopened.