Report the node of the XML that causes the error when calling `lint_ctx.warn` or `lint_ctx.error`, e.g. [here](https://github.com/galaxyproject/galaxy/blob/90871e8926ab70e8fa93a1a4df58b02a31993bc2/lib/galaxy/tool_util/linters/tests.py#L194). So far we do this in all linters. This can then be used in the language server to better guide the tool developer.