When showing the "Show blame prior to this change" and the commit in question has renamed the file, we cannot reliably link to the file at the parent, because we don't know the previous name of the file.

Example: (The commit from Dave)
https://sourcegraph.com/.api/blame/github.com/sourcegraph/sourcegraph@dd34d1b/stream/docker-images/syntax-highlighter/crates/syntax-analysis/src/highlighting/syntect_html.rs