Though we currently have the knowledge of where the `key` for an event binding appears during parsing, we do not propagate this information to the output AST. This means that once we produce the template AST, we have no way of mapping a template position to the key span alone. The best we can currently do is map back to the `sourceSpan`. This presents problems downstream, specifically for the language service, where we cannot provide correct information about a position in a template because the AST is not granular enough. This is essentially identical to the change from #38898, but for event bindings rather than input bindings. PR Close #39609
Tests in this directory are excluded from running in the browser and only run in node.