runtime-adapter: rustdoc fails on unresolved links to Runner in src/exec.rs #999

Found while validating #955; the problem is already on dev and appeared earlier in #870 and #937. Related to #833.

RUSTDOCFLAGS="-D warnings" cargo doc --no-deps for tests/runtime-adapter fails on unresolved intra-doc links in src/exec.rs (dev f60235a):

• line 3, in the module doc: [Runner];
• line 483: [Runner];
• line 502: [Runner::next_message].

Runner is nvx::exec::Runner. Only src/worker/executions.rs imports it, so these links in src/exec.rs don't resolve.

To fix:

• make the links resolve in every configuration the adapter's documentation is built for, for example with full paths, or reword them;
• consider building the adapter's documentation with -D warnings in CI. It isn't a CI step today, which is why CI doesn't catch this.