Native/Symbolicate: document limitations of fallback debug IDs for `.o` files

[kahest]

Related: getsentry/symbolicator#1240

Rationale: Fallback debug IDs we generate by hashing the executable section have a chance for collision, resulting in misleading stacktraces. This fact and possible mitigation should be discoverable, e.g. in troubleshooting sections of the docs

Note: According to getsentry/symbolicator#1240 (comment), this is not necessarily limited to .o files

[getsantry]

Routing to @getsentry/product-owners-issues-source-maps for triage ⏲️

[getsantry]

Routing to @getsentry/product-owners-sdks-web-frontend for triage ⏲️

[getsantry]

Routing to @getsentry/product-owners-sdks-native for triage ⏲️