syntax_data: {"ast_node_type":"other","tokens":[{"end":77,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:     // We know that `b` is the shorter string, so we don't need to check `a`.
context_before:     // If either string is empty, the distance is the length of the other.
context_after:     if b.len() == 0 {