Fix tracing of node_modules files not emitted by pages (#249)
Because the static SSR renderer doesn't emit files that exist in
`node_modules` (because we take advantage of node's native `require`
resolution), any paths that traced into `node_modules` would output the
full file system path. It's just verbose and annoying.
Co-authored-by: Tobias Koppers <tobias.koppers@googlemail.com>
